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  • Ultrastructure  (758)
  • Drosophila melanogaster  (138)
  • Springer  (896)
  • American Physical Society
  • 1980-1984  (419)
  • 1975-1979  (477)
  • 1940-1944
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  • 1
    Electronic Resource
    Electronic Resource
    The ovicidal activity ofcis-dehydromatricaria ester: time-dependance of its enhancement by UV light (1984)
    Springer
    Cellular and molecular life sciences 40 (1984), S. 1396-1397 
    Details
    ISSN: 1420-9071
    Keywords: Drosophila melanogaster ; ovicidal activity ; dehydromatricaria ester ; toxicity, enhancement by UV ; polyacetylenic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Freshly laid eggs ofDrosophila melanogaster were treated with the polyacetylenic compoundcis-dehydromatricaria ester. The toxicity of the chemical was enhanced by treatments with long-wavelength ultraviolet light, and the maximum effect was observed when the UV irradiation was performed 4–5 h after the initial contact of the eggs with the chemical.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951909
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure of differentiating preameloblasts from tooth germs of the permanent dentition ofMacaca mulatta andMacaca arctoides (1981)
    Springer
    Calcified tissue international 33 (1981), S. 603-618 
    Details
    ISSN: 1432-0827
    Keywords: Preameloblasts ; Tooth germs ; Monkey ; Enamel ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Cytodifferentiation of inner enamel epithelium and the adjacent connective tissue from the tip of the cervical loop to the initiation of enamel elaboration in twoMacaca species was examined. Ten- to twelve-month-old specimens were fixed by perfusion and the permanent tooth buds were prepared for transmission electron microscopy. At the cervical loop proper, inner enamel epithelium cells have lobed nuclei, a paucity of cytoplasm, and wide extracellular spaces; the basal lamina facing the dental papilla is straight. With increasing distance from the tip of the cervical loop, the following changes occur gradually: (a) preameloblasts elongate from 15 to 45 µm, and their organelles, particularly mitochondria and profiles of rough endoplasmic reticulum, become more numerous; (b) extracellular spaces decrease between preameloblasts starting at the basal (infranuclear) end; (c) the basement membrane becomes convoluted and associated with aperiodic fibers; (d) preodontoblast projections penetrate the aperiodic fibers; (e) collagen fibers subjacent to the basement membrane increase in density, with particularly thick fibers paralleling the aperiodic fibers. These modifications occur within three-fourths of the distance from the tip of the cervical loop to the mineralization front. The condensation of preodontoblasts is followed immediately by predentin synthesis. Concomitantly, the basement membrane breaks down and the aperiodic fibers are engulfed by preameloblasts. Preameloblast projections penetrate junctional predentin, contact mineralized dentin, and enamel synthesis ensues. At this stage the ameloblast is 45 µm long, the nucleus is central or basal, the Golgi apparatus has migrated apically, but the Tomes' process has not yet formed. The results indicate that odontogenesis inMacaca monkeys more closely resembles human odontogenesis than does that in the murine rodents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409498
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  • 3
    Electronic Resource
    Electronic Resource
    Coquille de l'oeuf de caille: Étude ultrastructurale et cristallographique (1978)
    Springer
    Calcified tissue international 25 (1978), S. 145-159 
    Details
    ISSN: 1432-0827
    Keywords: Bird egg shell ; Ultrastructure ; Calcification ; Electron diffraction ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1μm thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010763
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural and microanalytical aspects of developing osteodentin in rat incisors (1977)
    Springer
    Calcified tissue international 24 (1977), S. 215-222 
    Details
    ISSN: 1432-0827
    Keywords: Mineralization ; Osteodentin ; Intracellular ; Ultrastructure ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Newly formed osteodentin obtained from the anterior extremities of fetal or young rat incisors was observed by means of electron microscopy and electron probe X-ray microanalysis. Cells related to osteodentin formation frequently showed membrane bound intracellular bodies containing varying amounts of fine, needle-shaped crystals, which were identified as apatite. The intracellular clusters of apatite crystals were extruded from the cells through membrane fusion or cellular degeneration. These extracellular clusters seemed to be gradually incorporated into the mineralizing collagenous matrix, which developed around them. Frequent occurrence of dense, dotshaped or filamentous profiles suggested that the dense bodies seen in the perinuclear regions or in the Golgi area were the sites of crystal formation. Energy dispersive X-ray point analysis showed that the intracellular or extracellular apatite clusters contained sulfur in a concentration higher than was present in the mineralizing collagenous matrix. Furthermore, wave dispersive X-ray line analysis showed that the concentration of sulfur was higher in the osteodentin matrix than in the dentin matrix. The sulfur detected is presumed to be contained in acid mucopolysaccharides, which were distributed more heavily in the osteodentin matrix than in the dentin matrix. On the basis of these data, it was concluded that the unique chemical and structural characteristics of the osteodentin result primarily from the incorporation of apatite clusters of intracellular origin and associated acid mucopolysaccharides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223319
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  • 5
    Electronic Resource
    Electronic Resource
    Studies on the biology of fish bone. III. Ultrastructure of osteogenesis and resorption in osteocytic (cellular) and anosteocytic (acellular) bones (1979)
    Springer
    Calcified tissue international 28 (1979), S. 43-56 
    Details
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteogenesis ; Fish bone ; Osteocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The comparative ultrastructure of fish bone osteogenesis and resorption induced by scale removal was described in the osteocytic (cellular-boned)Carassius auratus and the anosteocytic (acellular-boned)Tilapia macrocephala. Osteocytes, present in osteocytic bone, were lacking in anosteocytic bone. In osteocytic bone the osteoblast secreted a collagenous preosseous matrix in which it became enmeshed and then was termed a preosteocyte. When the preosseous matrix mineralized, the preosteocyte was termed an osteocyte and was completely surrounded by bone. In anosteocytic bone the osteoblasts receded from the mineralizing front and never became trapped as osteocytes. During resorption, types A and B resorptive cells, present in both bone types, invaded the matrix and demineralized the osseous zone. These cells were characterized by large amounts of granular endoplasmic reticulum and intracellular inclusions containing crystal-like material. Although functionally similar to mammalian osteoclasts, these cells lacked a characteristic ruffled border and were not multinucleated. The osteocytes of cellular bone did not appear to be involved during demineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441217
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  • 6
    Electronic Resource
    Electronic Resource
    The ultrastructure of the zygospore in Endogone flammicorona Trappe & Gerdemann (1976)
    Springer
    Mycopathologia 59 (1976), S. 117-123 
    Details
    ISSN: 1573-0832
    Keywords: Ultrastructure ; Zygospore ; Mycorrhizal fungus ; Flaming crown
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructural organization of the spores of the sporocarp of Endogone flammicorona was studied. Two types of organization are described. Initially the spore possessed a vacuolate protoplasm and was bound by two cell wall layers. The spore was surrounded by a hyphal mantle formed of a sheet of vacuolized hyphae with uniformly thin walls. Secondly, although the ultrastructural features of the spore appeared the same, it was now surrounded by a hyphal mantle with unevenly thickened walls (i. e., the so-called flaming crown) due to the gradual and irregular deposition of granules and lamellae. This crown gives the spore its most commonly observed morphological feature and is the preminent character employed taxonomically to speciate Endogone flammicorona Trappe & Gerdemann.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00493564
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  • 7
    Electronic Resource
    Electronic Resource
    Localization of cells capable of transdetermination in a specific region of the male foreleg disk ofDrosophila (1977)
    Springer
    Development genes and evolution 182 (1977), S. 69-74 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Male foreleg disk ; Capacity of transdetermination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the male foreleg disk ofDrosophila melanogaster the cells capable of transdetermination are clustered in a specific region within the upper half of the disk. Cells outside this region cannot transdetermine under any of the experimental conditions thus far applied. Transdetermination occurs when cells capable of transdetermination are stimulated to a certain extent of additional proliferation. This can be achieved either by exposing these cells at a wound surface of an intact fragment, or by dissociation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848088
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  • 8
    Electronic Resource
    Electronic Resource
    Localized synthesis of specific proteins during oogenesis and early embryogenesis inDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 151-165 
    Details
    ISSN: 1432-041X
    Keywords: Oogenesis ; Embryogenesis ; Two-dimensional gels ; Protein synthesis ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protein synthesis in egg follicles and blastoderm embryos ofDrosophila melanogaster has been studied by means of two-dimensional gel electrophoresis. Up to 400 polypeptide spots have been resolved on autoradiographs. Stage 10 follicles (for stages see King, 1970) were labelled in vitro for 10 to 60 min with35S-methionine and cut with tungsten needles into an anterior fragment containing the nurse cells and a posterior fragment containing the oocyte and follicle cells. The nurse cells were found to synthesize a complex pattern of proteins. At least two proteins were detected only in nurse cells but not in the oocyte even after a one hour labelling period. Nurse cells isolated from stages 9, 10 and 12 follicles were shown to synthesize stage specific patterns of proteins. Several proteins are synthesized in posterior fragments of stage 10 follicles but not in anterior fragments. These proteins are only found in follicle cells. No oocyte specific proteins have been detected. Striking differences between the protein patterns of anterior and posterior fragments persist until the nurse cells degenerate. In mature stage 14 follicles, labelled in vivo, no significant differences in the protein patterns of isolated anterior and posterior fragments could be detected; this may be due to technical limitations. At the blastoderm stage localized synthesis of specific proteins becomes detectable again. When blastoderm embryos, labelled in vivo, are cut with tungsten needles and the cells are isolated from anterior and posterior halves, differences become apparent. The pole cells located at the posterior pole are highly active in protein synthesis and contribute several specific proteins which are found exclusively in the posterior region of the embryo. In this study synthesis of specific proteins could only be demonstrated at those developmental stages which are characterized by the presence of different cell types within the egg chamber, while no differences were detected when stage 14 follicles were cut and anterior and posterior fragments analyzed separately. The differences in the pattern of protein synthesis by pole cells and blastoderm cells indicate that even the earliest stages of determination are reflected by marked changes at the biochemical level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848268
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  • 9
    Electronic Resource
    Electronic Resource
    Étude en microscopie électronique et par cytophotométrie à balayage de la structure et de la distribution de la chromatine dans les noyaux des cellules cartilagineuses deTriturus cristatus âgés au cours de la régénération (1978)
    Springer
    Development genes and evolution 184 (1978), S. 195-211 
    Details
    ISSN: 1432-041X
    Keywords: Ultrastructure ; Scanning cytophotometry ; Chromatin ; Chondrocytes ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.
    Notes: Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer. Changes in the ultrastructure of the cytoplasm during regeneration were also studied. It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed. Changes in the nuclear structure are observed prior to the cytoplasmic modifications. It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt. We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848254
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  • 10
    Electronic Resource
    Electronic Resource
    A correlation between juvenile hormone deficiency and vitellogenic oocyte degeneration inDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 257-263 
    Details
    ISSN: 1432-041X
    Keywords: Juvenile hormone ; Precocene ; Drosophila melanogaster ; Oocyte degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary It is known from previous work that juvenile hormone (JH) is required to initiate vitellogenin uptake into maturing oocytes ofDrosophila melanogaster, but additional requirements for this hormone during oocyte maturation have not been fully understood. To determine if early vitellogenic oocytes (stages 8 and 9) require JH for continued development, these oocytes were transplanted toDrosophila female and male hosts which were rendered deficient in JH by three methods. Implanted stage 9 and usually stage 8 oocytes were found to degenerate in JH-deficient hosts unless ZR-515, a JH analogue, was applied to the host shortly after implantation. These results were confirmed during in situ ovary development. JH deficiency was produced in gravid females, and ovaries examined at subsequent time intervals were found to be deficient in stage 8–10 oocytes as early as 6 h after treatment. Degenerating oocytes corresponding to these stages were commonly found. ZR-515 prevented oocyte degeneration during at least the first 8 h and continued to support stage 8–10 oocyte development 24 h after application to these females. The results suggest that JH is required not only for initiation but also for continuation of vitellogenin uptake and oocyte development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848413
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  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848768
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  • 12
    Electronic Resource
    Electronic Resource
    Effect of 20-hydroxyecdysone on protein synthesis in wing discs ofDrosophila melanogaster (1983)
    Springer
    Development genes and evolution 192 (1983), S. 366-368 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Wing discs ; 20-Hydroxyecdysone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Full wing disc evagination requires about 10 h of continuous exposure to 20-hydroxyecdysone. The synthesis of two polypeptides is increased when wing discs are subjected to short exposure (4 h) to the hormone, and their synthesis is dependent on hormone. A second group of proteins increased in synthesis only after longer hormonal treatment (12 h); however, the increased synthesis of these proteins can be induced by withdrawing hormone after short exposure. The results of this study are consistent with the model of sequential gene activation by 20-hydroxyecdysone proposed by Ashburner et al. (1974).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848818
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  • 13
    Electronic Resource
    Electronic Resource
    Genetic analysis of pattern-formation in the embryo ofDrosophila melanogaster (1977)
    Springer
    Development genes and evolution 183 (1977), S. 249-268 
    Details
    ISSN: 1432-041X
    Keywords: Pattern-formation ; Embryogenesis ; Maternal-effect mutants ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationbicaudal (Bull, 1966) causes embryos to develop a longitudinal mirror image duplication of the posteriormost abdominal segments, while head and thorax are missing. These embryos occur with varying frequencies among eggs laid by mutant females, irrespective of the paternal genotype. Recombination and deletion mapping indicate thatbicaudal (bic) is a recessive, hypomorphic, maternal-effect mutation mapping at a single locus on the second chromosome ofDrosophila melanogaster close tovg (67.0±0.1). The frequency of bicaudal embryos depends on the age of the mother, her genetic constitution and the temperature at which she is raised. Best producers are very young females hemizygous forbic (bic/Df(2)vg B ) at 28° C. Under these conditions 80% to 90% of the eggs which differentiate can show the bicaudal embryo phenotype. Upon ageing of the mother the frequency of bicaudal embryos declines rapidly, and most of the eggs develop the normal body pattern. Temperature shift experiments suggest a temperature-sensitive period at the onset of vitellogenesis. The mutation causes several types of abnormalities in the segment pattern of theDrosophila embryo, which are interpreted as various degrees of expression of the mutant character. The most frequent abnormal phenotype is the symmetrical bicaudal embryo with one to five abdominal segments duplicated. Less frequent are asymmetrical types, in which the smaller number of segments is always in the anterior reversed part. Other phenotypes are embryos with missing or rudimentary heads, and embryos with irregular gaps in the segment pattern. In bicaudal embryos, the pole cells, formed at the posterior pole of the egg prior to blastoderm formation, are not duplicated at the anterior. The significance of thebicaudal phenotypes for embryonic pattern-formation inDrosophila is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00867325
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  • 14
    Electronic Resource
    Electronic Resource
    The cytoplasmic architecture of the egg cell ofSmittia spec. (Diptera, Chironomidae) (1977)
    Springer
    Development genes and evolution 183 (1977), S. 233-248 
    Details
    ISSN: 1432-041X
    Keywords: Cytoplasmic architecture ; Ultrastructure ; Insect egg ; Pattern formation ; Yolk ; Cytoplasma-Architektur ; Ultrastruktur ; Insekten-Ei ; Musterbildung ; Dotter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Das Ei der ZuckmückeSmittia spec. wurde licht- und elektronenmikroskopisch untersucht. Die vorliegende Arbeit beschreibt den Bau des Periplasmas und des Dotter-Endoplasma-Systems vor Bildung der Polzellen. 2. Das Periplasma, nach außen vom Oolemm und einer mehrschichtigen Eihülle begrenzt, besteht aus einer ribosomenreichen cytoplasmatischen Matrix, in die vor allem Mitochondrien und ER-Zisternen, wenig annulate lamellae und gelegentlich Golgi-Apparate eingelagert sind. Mikrotubuli wurden nur selten nachgewiesen. Öfters sind Anhäufungen einer dichten granulierten Substanz zu beobachten, die in ihrer Struktur dem Oosom-Material ähnelt. 3. Das Dotter-Endoplasma-System stellt ein Netzwerk aus Cytoplasma dar, in das Proteid-Dotterkugeln, Lipidtröpfchen sowie Glycogen-Anhäufungen eingelagert sind. Das Endoplasma, das sich zu 3–7 Plasma-Inseln erweitern kann und unmittelbar in das Periplasma übergeht, besteht wie dieses aus einer cytoplasmatischen Matrix und enthält die gleichen Zellelemente wie das Periplasma. Rosettenförmige Membran-Strukturen werden als “nuclear envelope organizing center” gedeutet. 4. Drei der sorgfältig analysierten Eier enthielten je 2 Kerne; sie lagen in Plasma-Inseln in der hinteren Eihälfte. 5. Sowohl im Periplasma wie im Dotter-Endoplasma-System sind alle Zellelemente unregelmäßig verteilt. Eine besondere Anordnung oder Zonierung ist nicht zu erkennen. 6. Die räumliche Verteilung der erfaßten Eikomponenten liefert keine Hinweise auf eine Funktion dieser Komponenten als Determinanten für die embryonale Musterbildung.
    Notes: Summary 1. Eggs of the midgeSmittia were investigated by light microscopy and transmission electron microscopy. This paper describes elements and architecture of periplasm and yolk endoplasm before the formation of pole cells. 2. The periplasm is coated externally by the oolemma and a multilayered egg shell. The periplasm consists of a cytoplasmic matrix rich in ribosomes; it contains mitochondria and ER cisternae, some annulate lamellae and an occasional Golgi complex. Microtubuli were demonstrated only rarely. Accumulations of a dense granulated substance resembling in its structure the oosome material were frequently observed. 3. The yolk endoplasm is a cytoplasmic network embodying proteid yolk particles, lipid droplets and accumulations of glycogen. The endoplasm is continuous with the periplasm and shows the same cell constituents. It may form between 3 and 7 cytoplasmic islands free of yolk particles. Rosette-shaped membranous structures in the yolk endoplasm are interpreted as nuclear envelope organizing centres. 4. Three carefully analysed eggs contained 2 nuclei each. both nuclei were situated in the posterior egg half. 5. Periplasm and yolk endoplasm are characterized by random distribution of cell elements. No zonation or special accumulations could be recognized. 6. The spatial distribution of the egg components studied did not indicate that any of these components could function as a determinant in embryonic pattern formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00867324
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  • 15
    Electronic Resource
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    Ultrastructure of a fertilized barnacle egg (Pollicipes polymerus) with peristaltic constrictions (1977)
    Springer
    Development genes and evolution 181 (1977), S. 333-355 
    Details
    ISSN: 1432-041X
    Keywords: Barnacle eggs ; Constriction rings ; Microfilaments ; Ultrastructure ; Peristalsis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The egg ofPollicipes polymerus, the common intertidal gooseneck barnacle, has been studied by electron microscopy. Constriction rings, similar to the contractile rings of cleaving cells and polar lobes, move unidirectionally from the animal to the vegetal pole of newly fertilized eggs. This is referred to as peristaltic constriction. The present paper describes the fine structure of the egg during first polar body formation and peristalsis. 2. During formation of the polar body, dense bodies are produced by the Golgi and extracellular plaques are observed. Thin microfilaments (40–60 Å) are in the egg adjacent to the polar body. 3. In eggs undergoing peristalsis, the appearance of extracellular spheres, flocculent material and filaments is observed. Intracellularly large numbers of multivesiculate bodies, glycogen granules, mitochondria and protein-carbohydrate and lipid yolk bodies are seen at the level of constriction. 4. Thin microfilaments are found in the cortical area of newly-fertilized eggs exclusively in peristaltic constriction rings. Filaments are oriented primarily in a meshwork, although circumferentially-oriented filaments are also found in rings near the vegetal pole. Microvilli extend into the space created between a constriction and the elevated egg membrane. 5. A model is proposed to explain the peristalsis in this species. It is suggested that information from a pacemaker region activates peristalsis by affecting filament polymerization and orientation. One function of peristalsis may be elongation of the egg from a sphere to an ovoid, although other possibilities such as elevation of the egg membrane, segregation of the lipid yolk to the vegetal pole and predetermination of the first cleavage plane are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848060
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  • 16
    Electronic Resource
    Electronic Resource
    Changes in cell surface proteins of culturedDrosophila cells exposed to 20-hydroxyecdysone (1983)
    Springer
    Development genes and evolution 192 (1983), S. 103-107 
    Details
    ISSN: 1432-041X
    Keywords: Cell Surface ; Drosophila melanogaster ; 20-hydroxyecdysone ; protein changes ; Two-dimensional polyacrylamide gel electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Drosophila cell lines have provided popular material for study of the mechanisms by which steroid hormones regulate cellular events. Previous investigations at the organismic or organ level have suggested that ecdysteroids are bound by a cytoplasmic receptor, and that the resulting complex translocates to the nucleus where it results in active transcription of a few genes. The protein products of these primary responding genes then modulate a larger series of secondary transcriptional changes. In cultured cells, other investigators have detected the hormonally-induced synthesis of only 4–5 new polypeptides through 72 h of treatment. Although these proteins may represent the gene products associated with the primary response, this small number of changes is surprising in view of the rapid morphological alteration of the cells and changes in such surface-mediated behavior as substrate adhesion and agglutinability observed within the same time interval. In this report, we show that lactoperoxidase-catalyzed radioiodination followed by 2-dimensional polyacrylamide gel electrophoresis and autoradiography provide an effective protocol for visualizing cell surface proteins of a Drosophila cell line. Among the more than 175 labeled species detected, comparisons of control cells with those treated by 20-hydroxyecdysone for 72 h shows at least 27 differences. We interpret these differences as the result of the secondary transcriptional response to the hormone.
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    Preblastoderm mosaics of mutants of the bithorax-complex (1982)
    Springer
    Development genes and evolution 191 (1982), S. 331-334 
    Details
    ISSN: 1432-041X
    Keywords: Genetic mosaics ; Cell autonomy ; Cell affinities ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InDrosophila melanogaster, segmental specification takes place in groups of cells around the blastoderm stage. This segmental specification requires the function of the genes of the bithorax-complex. We have studied preblastoderm mosaics (gynandromorphs) of mutant (bx 3,pbx, Ubx, Ubx 80) and wildtype (heterozygotes for these alleles) cells. The results show a total cell autonomy in the differentiation of both wildtype and homoeotially transformed cells. However, several unexpected phenotypes were found. They are discussed in terms of the function of the bithorax genes and early interactions between mutant and wildtype territories.
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    URL: http://dx.doi.org/10.1007/BF00848493
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  • 18
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    Ultrastructure of collagen in sea urchin embryos (1979)
    Springer
    Development genes and evolution 186 (1979), S. 65-70 
    Details
    ISSN: 1432-041X
    Keywords: Sea urchin ; Embryo ; Collagen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Collagen fibrils with a main period banding of 610 Å and 220 Å in width were observed in the blastocoel of 72-h embryos of the sea urchin,Strongylocentrotus purpuratus. Non-striated fibrils of 50 Å diameter were also observed. The collagen is seen in highest concentration in the vicinity of mesenchyme cells which are richly endowed with endoplasmic reticulum and secretory vesicles. A role for collagen in cell attachment, orientation and spicule formation is discussed.
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    URL: http://dx.doi.org/10.1007/BF00848108
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  • 19
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    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
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    Migration and division of cleavage nuclei in the gall midge,Wachtliella persicariae (1980)
    Springer
    Development genes and evolution 188 (1980), S. 65-73 
    Details
    ISSN: 1432-041X
    Keywords: Nuclear migration ; Cleavage ; Microtubules ; Ultrastructure ; Gall midge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the eggs ofWachtliella persicariae the cleavage nuclei move relative to the surrounding ooplasm. This ‘active’ migration is caused by an organelle whose ultrastructure was studied throughout the mitotic cycle. It consists of a greatly enlarged polar cytaster derived from the mitotic apparatus, linked to the nucleus by 100 Å filaments. The microtubules of the cytaster were found only during periods of active nuclear migration, i.e., from the onset of anaphase to the early prophase of the next mitotic cycle. They are always solitary and follow the course of the astral rays, which are known to temporarily adhere to peripheral structures of the egg cell and to exert tractive forces. In contrast to the cytaster microtubules, the microtubules in the spindle are bundled and persist from early metaphase through late telophase. During ontogenesis the first migration cytaster is built up between 3 and 12 min after oviposition near the anterior egg pole, in the vicinity of the sperm nucleus. In non-inseminated eggs time lapse films show a migration cytaster to develop autonomously in a region free from nuclei, but it does not follow the normal path of the male pronucleus. In several cases the female pronucleus, which remains without a cytaster of its own, was observed to move to the cytaster generated in the absence of the male pronucleus. Whether or not it is adhering to a nucleus, the cytaster divides into two at the correct time, i.e, corresponding to the first cleavage division in fertilized eggs. In some non-inseminated eggs this type of ‘pseudocleavage’ has been observed to occur repeatedly, giving rise to an increasing number of anucleate cytasters.
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    URL: http://dx.doi.org/10.1007/BF00848611
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  • 21
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    Patterns of protein synthesis in salivary glands ofDrosophila melanogaster during larval and prepupal development (1981)
    Springer
    Development genes and evolution 190 (1981), S. 351-357 
    Details
    ISSN: 1432-041X
    Keywords: Salivary gland ; Protein synthesis ; Larval development ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Patterns of protein synthesis in the salivary glands ofDrosophila melanogaster have been studied throughout late larval and prepupal development by pulse labelling the tissues with35S-methionine. Specific changes to the pattern of proteins synthesized during development are found and the significance of these changes is discussed in view of the known changes in gene (puffing) activity which occur at the same times. We review the problem of salivary gland function in “prepupal”Drosophila.
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  • 22
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    Detection of clones in the nervous system ofDrosophila melanogaster (1977)
    Springer
    Development genes and evolution 183 (1977), S. 165-169 
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    ISSN: 1432-041X
    Keywords: Clones ; Nervous system ; Shibire ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic recombination was induced, by X-irradiation at the blastoderm stage, in flies heterozygous for one of the temperature-sensitive paralytic mutationsshibire andtp-2. The results show that these mutations can be used to detect the presence of clones in the central nervous system through the temperature-sensitive paralysis of individual legs. Mitotic recombination can also be used to examine the effects of these mutations in the peripheral nervous system; shibire is thus shown to affect the function of sensory neurons.
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  • 23
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    Isozymic patterns and functional states of cell lines ofDrosophila melanogaster cultured in vitro. II (1976)
    Springer
    Development genes and evolution 180 (1976), S. 107-119 
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    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Cell lines ; Isoenzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our previous isoenzyme investigation ofDrosophila melanogaster cell lines in vitro has been completed with twelve further enzyme systems. The “enzyme profiles” seem to be in good agreement with a previous hypothesis concerning the precise origin of these cell lines (probably from imaginal discs or nervous tissues). Our results have been summarized with reference to the biochemical genetic map ofDrosophila melanogaster in order to consider a possible functional organization of the genome.
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    URL: http://dx.doi.org/10.1007/BF00848101
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    A study of the female germ line in mosaics ofDrosophila (1978)
    Springer
    Development genes and evolution 184 (1978), S. 41-56 
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    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Female germ line ; Mosaics ; Stem cell divisions ; Metafemale ; Sterility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our report presents an analysis of the development and dynamics of the female germ line inDrosophila. Females were produced that were mosaic either for attached-X chromosomes $$(\widehat{XX})$$ and a ring-X (triplo-X-diplo-X), or for $$\widehat{XX}$$ and a marked Y-chromosome $$(\widehat{XX}/Y - \widehat{XX}/O)$$ . The germ-line and genitalia of these females were analysed by direct microscopic observation or by examination of the progeny. Eggs derived from triplo-X germ cells were hardly capable of supporting development, with most of the zygotes dying during embryonic development. The analysis of the germ line was therefore carried out mainly by direct observation of histochemically stained developing oocytes in the ovaries of mosaic females. The total germ cell population of both ovaries of a female was mosaic in 22–29% of the tested animals. From this frequency of mosaicism we estimated the number of functional primordial germ cells to be betwen 3 and 6 cells at the blastoderm stage. At this stage the cell lineages for the left and right ovary are not yet separated. The germ cell population of individual ovarioles was frequently mosaic which shows that the few stem cells in an ovariole are recruited as a group and are not clonal descendants of a single ancestor cell per ovariole. An analysis of the sequential pattern of oocyte-nurse cell cysts in mosaic ovarioles revealed that neighbouring cysts tend to be of the same genotype. This suggests that the stem cells of the adult ovaries preferentially divide in bursts, one of them giving rise to two, three and sometimes even more cystocytes in a row. In addition, the foci for lethality and sterility of the triplo-X condition were determined. Non-mosaic triplo-X females (metafemales) are hardly viable and invariably sterile. Using our mosaics, the focus forlethality could be mapped to a region very near the ventral prothoracic discs. The focus forsterility resides in the genitalia, since flies with triplo-X genitalia never laid any eggs, regardless of the genotype of their ovaries.
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    URL: http://dx.doi.org/10.1007/BF00848668
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  • 25
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    Rudimentary mutants ofDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 167-177 
    Details
    ISSN: 1432-041X
    Keywords: Pyrimidine biosynthesis ; rudimentary mutants ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The X-linkedrudimentary (r) mutants ofDrosophila melanogaster are pyrimidine auxotrophs and require exogenous pyrimidines (Nørby, 1970; Falk, 1976). We have established a set ofrudimentary cell lines that are derived from embryos, homozygous for eitherr 1 orr 36. The enzymatic activities of the pyrimidine synthesizing enzymes were measured in the mutant lines. We have further investigated the nutritional requirements of the mutant cells in vitro by using a pyrimidine free culture medium. Ther 1 cell lines were found to express 3–7%dihydroorotase (DHOase) activity as compared to a wildtype cell line. Reducedaspartate transcarbamylase (ATCase) activity was measured in somer 1 cell lines whereas wildtypecarbamylphosphate synthetase (CPSase) activity is expressed in allr 1 cell lines. Ther 36 cell line expresses wildtype activity ofDHOase andCPSase. ATCase activity was found to be reduced to 10% of the wildtype activity. The mutant cell lines do not proliferate in pyrimidine free minimal medium and cell proliferation is obtained by the addition of crude RNA. Proliferation of ther 1 cells is restored by the supplementation of the minimal medium withdihydroorotate whereas proliferation of ther 36 cells is restored by supplementation with eitherdihydroorotate orcarbamylaspartate. The results demonstrate that therudimentary phenotypesr 1 andr 36 are expressed at the cellular level and that the two mutant cell types behave as cellular pyrimidine auxotrophs in vitro.
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    The isolation of functional pole cells from theDrosophila melanogaster maternal effect mutantmat(3)1 (1980)
    Springer
    Development genes and evolution 188 (1980), S. 127-132 
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    ISSN: 1432-041X
    Keywords: Pole cell isolation ; Maternal effect mutants ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A procedure for pole cell isolation has been developed that takes advantage of theDrosophila melanogaster maternal effect mutantmat(3) 1. Embryos derived from homozygousmat(3)1 mothers form exclusively pole cells. By outcrossing we could substantially increase the expressivity of the original mutant stock. We further introduced theTM8 balancer chromosome, which carries the dominant temperature sensitive mutationDTS-4. This allows the accumulation of large homozygousmat(3) 1 fly populations by eliminating the heterozygous flies at the restrictive temperature. Early embryos were mechanically fragmented and the cells were isolated by means of metrizamide step gradients. The isolated cells were demonstrated to exhibit the various ultrastructural and histochemical characteristics of pole cells. The isolated cells were transplanted into genetically marked host embryos. The germ line mosaics that were obtained indicate that the isolated cells represent functional pole cells. Proteins synthesized by the isolated pole cells during short term in vitro labelling with35S-methionine were compared to the proteins synthesized by blastoderm cells fromOregon-R embryos. At least one protein could be demonstrated in the pole cell samples that is not synthesized byOregon-R blastoderm cells. The method allows a fast and gentle isolation of highly enriched pole cell populations which are a prerequisite for the biochemical analysis of germ cell determination and differentiation.
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    Morphogenesis in the embryo ofDrosophila melanogaster — Germ band extension (1980)
    Springer
    Development genes and evolution 188 (1980), S. 163-177 
    Details
    ISSN: 1432-041X
    Keywords: Yolk sac ; Ultrastructure ; Embryogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes at the ultrastructural level during germ band extension in the embryo ofDrosophila melanogaster are described. Cytoplasmic connections between cells and the yolk sac are present during initial cellular movements. At this time, a continuous system of microfilaments is present adjacent to the membranes in the connections and at the periphery of the yolk sac. As germ band extension progresses, this system becomes discontinuous, and microfilaments are apparent only in the immediate vicinity of the connections. Cytoplasmic connections are disassembled at approximately the midpoint of extension; at the same time, extensive membrane associations develop between germ band cells and between these cells and adjacent yolk sac membranes. Positioning and orientation of cytoplasmic connections suggest that the yolk sac, via these connections, is actively involved in the cellular movements of early germ band extension.
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    The DNA content of polytene nuclei in midgut and Malpighian tubule cells of adultDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 381-384 
    Details
    ISSN: 1432-041X
    Keywords: Polyteny ; DNA content ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The amounts of DNA in midgut and Malpighian tubule cells of adult maleDrosophila melanogaster have been determined by Feulgen-DNA cytophotometry. The DNA values fall into discrete classes reflecting different levels of polyteny. The maximum level is 64C in the midgut, 256C in Malpighian tubules, and the modal values are 32C and 128C respectively. The data provide no evidence for extensive underreplication of heterochromatin. It is suggested that the reduced amount of satellite DNA found in the tissues of young adult flies may be a consequence of the fact that cycles of DNA replication started in the pre-adult stages are not completed until some hours after eclosion.
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    Retention of the differentiated state by larvalXenopus liver cells in primary culture (1978)
    Springer
    Development genes and evolution 185 (1978), S. 235-248 
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    ISSN: 1432-041X
    Keywords: Liver ; Primary culture ; Ultrastructure ; Albumin synthesis ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscopic analysis of primary cultures derived from larvalXenopus liver has shown that these cells, although they form only two-dimensional aggregates, retain and presumably also develop structural characteristics typical of liver parenchyma cells, such as bile canaliculi with microvilli and epithelial junctional complexes. As judged from structural criteria, primary cultures contain 80–90% hepatocytes. In contrast to the intact tissue, primary cultures showed excessive development of microfilaments, however. Incorporation of labeled amino acids has revealed further that the capacity for protein synthesis is maintained in culture and that synthesis of liverspecific protein albumin is maintained in vitro, even in liver cultures derived from thyrostatic tadpoles. This latter result suggests that initiation of albumin synthesis in the larval liver is probably not dependent upon thyroid hormones but rather reflects the protodifferentiated state of this tissue.
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    The dorsal/ventral compartment boundary inDrosophila: coincidence with the prospective operculum seam (1984)
    Springer
    Development genes and evolution 193 (1984), S. 133-138 
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    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Compartment boundary ; Operculum seam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Histochemical staining of the hypoderm ofDrosophila larvae for aldehyde-oxidase activity allowed detection of a row of cells destined to form the operculum seam, along which the pupal case opens when the adult ecloses. Analysis ofmal clones in hypoderms of gynandromorph larvae showed that the prospective operculum seam coincides, in part, with a line of clonal restriction that divides the thorax into dorsal and ventral halves. We propose that this line represents the embryonic dorsal/ventral compartment boundary
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    The effect of fat body on the differentiation in vitro of wing imaginal discs ofDrosophila melanogaster (1976)
    Springer
    Development genes and evolution 180 (1976), S. 73-77 
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    ISSN: 1432-041X
    Keywords: Ecdysones ; Imaginal discs ; Fat body ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of suboptimal levels of α-ecdysone on the differentiation in vitro ofDrosophila melanogaster wing discs was enhanced by the addition of larval fat body to the cultures. However, similar experiments with β-ecdysome showed no enhancement. It is suggested that a partial conversion of α-ecdysone to β-ecdysone by the fat body may well account for these results.
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    Developmental potentials of the cells of the male foreleg disc ofDrosophila (1977)
    Springer
    Development genes and evolution 181 (1977), S. 309-320 
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    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Male foreleg disc ; Pattern regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The developmental potentials of the four quadrants of the male foreleg disc ofDrosophila melanogaster were analysed by culturing excised quadrants for 3 days and 10 days in adult hosts prior to metamorphosis. 2. The cultured pieces underwent different types of pattern regulation in a circular direction. The upper medial piece was able to regenerate the missing structures of the disc, thus confirming the findings of earlier reports. The three remaining pieces could undergo pattern duplication in mirror-image symmetry. The lower medial piece revealed in addition a slight capacity for regeneration from the vertical cut surface. 3. The duplicating pieces differed markedly in their frequencies of pattern duplication: duplications occurred with very high frequencies in lower medial pieces, with intermediate frequencies in upper lateral pieces, and with very low frequencies in lower lateral pieces. 4. Both lower lateral and upper lateral pieces underwent a progressive loss of most markers with increasing culture time. 5. Claws were regenerated solely by upper medial pieces. 6. Transdetermined structures, too, were encountered only in upper medial pieces. 7. The results are discussed with respect to the two major current models of pattern regulation in imaginal discs, the “gradient model” and the “clock model”. 8. It is suggested that the differences in the frequencies of pattern duplication reflect the unequal spacing of circular positional values within the three duplicating quadrants. Under this assumption the data indicate a progressive decrease in the density of circular positional values with increasing distance from the upper medial quadrant of the disc.
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    Mutations of early neurogenesis inDrosophila (1981)
    Springer
    Development genes and evolution 190 (1981), S. 226-229 
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    ISSN: 1432-041X
    Keywords: Early neurogenesis ; Mutants ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Embryonic lethal mutations at the Notch locus are known to produce a conspicuous central nervous system hypertrophy accompanied by a hypotrophy of the epidermal sheath. We have studied several zygotic mutants belonging to four different autosomal complementation groups which produce the same phenotype. The embryonic development of the new mutants, as well as that of Notch, consists of an initial enlargement of the neurogenic region at the expenses of epidermal cell precursors. The possibility is discussed that these five loci are involved in the determination of neural and epidermal cell precursors.
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    Complete replication of DNA in polytene nuclei of salivary glands ofDrosophila melanogaster (1981)
    Springer
    Development genes and evolution 190 (1981), S. 237-240 
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    ISSN: 1432-041X
    Keywords: DNA replication ; Polytene salivary gland nuclei ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Combined cytophotometric and autoradiographic experiments are performed on individual polytene salivary gland nuclei of X/X-female and X/Y-male larvae ofDrosophila melanogaster, DNA measurements of unlabeled nuclei reveal complete douplings of all 4C DNA quantity during polytenization. These new data do not agree with the hypothesis of heterochromatic underreplication.
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    Trithorax: A new homoeotic mutation ofDrosophila melanogaster (1981)
    Springer
    Development genes and evolution 190 (1981), S. 365-369 
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    ISSN: 1432-041X
    Keywords: Selector genes ; Determination ; Homoeotic mutations ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary New alleles of thetrithorax locus have been isolated and analysed. The phenotypes of different allelic combinations confirm that a decrease or loss of function of the locus is responsible for homoeotic transformations of the adult thoracic and abdominal segments. Since neither these homoeotic transformations nor larval lethality are complemented by the previously described mutationRg-bx, it is concluded that the latter is an allele oftrithorax. The effect of near loss of function of thetrithorax locus after the completion of embryogenesis has been investigated by clonal analysis. This has produced two unexpected results: 1) there is a requirement for the activity of the locus after embryogenesis is completed; 2) the locus is required for the normal development of at least some mesothoracic structures. These results are discussed with respect to the selector gene hypothesis and other putative activator gene mutations.
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    Ultrastructural changes in the distal wing bud of the chick embryo after removal of the apical ectodermal ridge (1979)
    Springer
    Development genes and evolution 185 (1979), S. 333-346 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Limb bud ; Ultrastructure ; Cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural changes in the wing bud afterapical ectodermal ridge (A.E.R.) removal was studied to re-examine the issue of distal mesenchymal cell death. The A.E.R. of the right wing bud was removed microsurgically from chick embryos of stages 18 to 22 (HH 1951). The wing buds were examined at three hour intervals up to twelve hours after the operation with light, transmission and scanning electron microscopy. The main findings were: (1) Immediate and temporary shrinkage of the mesenchymal extracellular space 100 to 150 μm and chromatin condensation in the cells 50 to 75 μm from the wound. (2) Death of ectodermal and mesenchymal cells in the immediate vicinity of the wound. (3) Formation of a single squamous-like layer of mesenchymal cells to cover the wound. (4) Occasional evidence of cell death in the distal mesenchyme at later times after the operation. The pattern of cell death observed suggests only a traumatic etiology, and gives little evidence for the postulated developmental significance of cell death following A.E.R. removal.
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    Abrupt decline in the rate of accumulation of total protein and yolk in postvitellogenic egg chambers ofDrosophila (1983)
    Springer
    Development genes and evolution 192 (1983), S. 189-195 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila melanogaster ; Embryo Metabolism ; Protein biosynthesis ; Ovary ; Growth and development egg yolk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The accumulation of endogenously synthesized non-yolk proteins, and of exogenously derived yolk, was quantitated during oogenesis and embryogenesis ofDrosophila. Rates of non-yolk protein accumulation were calculated, and were correlated with polysome content at each developmental stage. Three distinct phases of non-yolk protein accumulation were observed: 1) relatively slow accumulation, lasting to stage 9 of oogenesis; 2) very rapid accumulation between stages 10 and 12 of oogenesis, when half of the protein of the mature egg is accumulated in less than 4 h; and 3) no further protein accumulation from stage 12 of oogenesis through at least the gastrula stage of embryogenesis. During phases 1 and 2, rates of non-yolk protein accumulation correlate well with the polysome content of egg chambers. Surprisingly, during the entire phase 3 the content of polysomes remains at high levels, even though no detectable protein accumulation occurs. This finding is in agreement with the low levels of protein synthesis that have been measured during early embryogenesis, and strongly suggests that late in oogenesis the efficiency of translation suddenly drops by about 20-fold. Moreover, our results imply that polysome content cannot always be directly correlated with protein synthetic activity.
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    The development of sensory nerves within the wing ofDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 226-233 
    Details
    ISSN: 1432-041X
    Keywords: Wing development ; Sensory neurons ; Differentiation ; Axonal outgrowth ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary TheDrosophila wing is a simple structure bearing many sensory neurons which form an elementary pattern of nerves within the veins, and provides a simple system for studying the formation of nerve pathways. A light-and electron-microscope study of the developing pupal wing was undertaken to establish the time at which the different classes of sensillum differentiate and to determine the arrangement of tissues within the wing during sensory axon out-growth in order to assess possible candidates for directing axon outgrowth. Major findings were 1. Wing development passes through three main stages: at 6–12 h after puparium formation the wing is flantened and secreting pupal cuticle; at 15–18 h the wing is dramatically inflated but is still a simple epithelium secreting pupal cuticle; at 21–24 h the wing collapses and begins to differentiate adult structures. 2. There are no persisting larval nerves which might act as pioneers or pathfinders for the later developing adult neurons. 3. Axon bundles are first observed during the 15–18 h stage prior to the pupal moult when the wing is still secreting pupal cuticle. 4. At this stage the wing is an inflated sac, without any veins or orderly arrangements of tracheae which might act as guides for axon outgrowth. Vein formation takes placeafter formation of the axon pathways. 5. The bristle axons grow along the anterior wing margin in close contact with the basal lamina of the epithelial cells, often within a gap between the processes of the epithelial cells, which could mechanically channel their out-growth. 6. The campaniform sensillum axons appear to navigate along the inner surface of the wing epithelium rather like the pioneer axons found in embryonic appendages of other insects. 7. Differentiation of sensory neurons takes place long before differentiation of the other cells associated with sensilla; most axons are present by 18 h when the wing is still secreting pupal cuticle but morphological differentiation of the bristle shaft and socket cells is not observed until about 42 h when the wing is secreting the cuticulin layer of the adult cuticle.
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    Genetic regulation of theAchaete-scute complex ofDrosophila melanogaster (1984)
    Springer
    Development genes and evolution 193 (1984), S. 242-245 
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    ISSN: 1432-041X
    Keywords: Chaetae ; Sensillae ; Differentiation ; Genetic regulation ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutants in two loci,hairy (h +) andextramacrochaetae (emc +), produce phenotypes corresponding to an excess of function of theachaete-scute complex (AS-C), that is, they cause the appearance of extra chaetae. These mutants, although recessive in normal flies, become dominant in the presence of extra doses of AS-C. Here we study the interactions between these three genes, in an attempt to elucidate their relationships. The results show that the insufficiency produced byh oremc mutants can be titrated by altering the number of copies of AS-C. Moreover, excess of function of AS-C produced by derepression mutants within the complex (Hairy-wing) can also be titrated by altering the number of wild type copies of+ oremc +. These specific interactions indicate that bothh + andemc + code for “repressors” of AS-C that interact with theachaete andscute region of the complex respectively.
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    Cell interactions in the generation of chaetae pattern inDrosophila (1984)
    Springer
    Development genes and evolution 193 (1984), S. 246-251 
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    ISSN: 1432-041X
    Keywords: Chaetae ; Differentiation ; Genetic regulation ; Pattern formation ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have already shown that theachaetae-scute complex (AS-C) ofDrosophila is regulated by two genes,hairy andextramacrochaetae. Using mutants in these genes, we have analysed how different levels of expression of AS-C affect the pattern of chaetae. The results indicate that the spatial distribution of chaetae results from cell interactions, probably by a mechanism of lateral inhibition. The results are discussed in view of the different theories of pattern formation.
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    Ultrastructure, histology, and innervation of the mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi (1978)
    Springer
    Calcified tissue international 26 (1978), S. 271-282 
    Details
    ISSN: 1432-0827
    Keywords: Shell formation ; Free nerve endings ; Ultrastructure ; Lymnaea stagnalis ; Biomphalaria pfeifferi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.
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    Ultrastructural localization and gradient of activity of alkaline phosphatase activity during rodent odontogenesis (1982)
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    Calcified tissue international 34 (1982), S. 273-279 
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    ISSN: 1432-0827
    Keywords: Odontogenesis ; Ultrastructure ; Alkaline phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The ultrastructural localization and gradient of activity of alkaline phosphatase were studied with respect to cell differentiation, matrix synthesis, and matrix mineralization in the incisor and molar teeth of 4-day-old Sprague-Dawley rats. The animals were perfused intracardially at room temperature with 2.5% glutaraldehyde in 0.1M sodium cacodylate (pH 7.4) with 3–4% sucrose. The jaws were dissected, immersion-fixed for 24 h, and the incisor and molar tooth germs removed. These were demineralized in 10% EDTA in NaOH (pH 7.4) with 7% sucrose. After reactivation of the enzyme with 0.1M MgCl in Tris-maleate buffer (pH 7.4) at 4°C, the teeth were incubated for alkaline phosphatase in a medium consisting of 6 ml 3% sodiumβ-glycerophosphate, 4 ml 0.2M Tris-HCl buffer (pH 9.2), 3 ml 1.6% MgSO4, 12 ml 0.5% lead citrate (pH⋍12), and 2.1 g sucrose. The pH was adjusted to 9.2 with 0.2M HCl, the volume made up to 30 ml, and the solution centrifuged for 10 min at 5000 rpm. Control teeth were incubated in medium minus the substrate. Finally, the specimens were routinely post-fixed and embedded for sectioning and examination with a Philips 300 electron microscope. A gradient of alkaline phosphatase activity was mapped along the developing teeth in the cells of the stratum intermedium, the proximal borders of the ameloblasts, the early dentine matrix, the predentine-dentine border, matrix vesicles, and the plasma membranes of odontoblasts and subodontoblast cells. The gradient of alkaline phosphatase activity was evident in the forming tooth from the cervical loop to the crown apex and was related to the cellular events, matrix synthesis, and matrix mineralization occurring during odontogenesis.
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    Ultrastructural study of apatites in human urinary calculi (1980)
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    Calcified tissue international 31 (1980), S. 93-108 
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    ISSN: 1432-0827
    Keywords: Calculus ; Ultrastructure ; Apatite ; Transmission ; Scanning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Using transmission and scanning electron microscopy, we have studied the ultrastructure of a number of urinary calculi, mainly composed of calcium phosphate. Three fundamental kinds of calcium phosphates were detected: nonstoichiometric carbonate apatite, nonhexagonal octacalcium phosphate, and calcium-magnesium whitlockite. The influence that the organic matter, substitutions in the phosphate lattice of CO3 and Mg, and apatitic stoichiometry have on the ultrastructure of the calcium phosphate calculi has been detailed. An originating apatitic unity named U2 is assumed to be the responsible for all the different structures of calcium apatites appearing in renal calculi. On the basis of our observations, a mechanism whereby apatites grow is postulated; magnesium functions as an inhibitor for the growing mechanism.
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    Ultrastructural localization of calcium in the mandibular condylar growth cartilage of the rat (1980)
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    Calcified tissue international 30 (1980), S. 27-34 
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    ISSN: 1432-0827
    Keywords: Ultrastructure ; Calcium ; Cartilage ; Vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The potassium pyroantimonate technique was utilized for the selective subcellular localization of calcium in the mandibular condylar cartilage of 1-day-old rats. Electron dense calcium pyroantimonate precipitates were localized principally in mitochondria and at the cell membrane of the chondrocytes. In addition, small intracellular vesicles 0.1–0.2µm in diameter were observed in proximity to the cell membrane of chondrocytes of the mid-hypertrophic zone. The results suggest that these vesicles were being extruded from the cell into the extracellular matrix. Energy-dispersive analysis by X-rays confirmed that calcium is the principal cation of the electron-dense precipitates.
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    Length and shape of enamel crystals (1984)
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    Calcified tissue international 36 (1984), S. 550-555 
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    ISSN: 1432-0827
    Keywords: Enamel crystals ; Length ; Shape ; Apatite ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An original method for fractionating and preparing isolated crystals of homogeneous size was developed. It was demonstrated that enamel apatite crystals are at least 100 µm long. The flexibility of the very long crystallites was demonstrated. Crystal curvatures, accounting for the irregular course of the prisms through the enamel thickness, were visualized and measured. It was shown that in the deep forming enamel layer, lateral branches may grow out of the crystals and crystal fusing often occurs, inducing the crystallites to assume pyramidal shapes with their wide bases pointing toward the dentino-enamel junction and one or two tops toward Tomes' processes. During the maturation process, the two tops of the still immature crystals also fuse so that the mature crystals acquire a rodlike aspect, with parallel faces and steplike graduations along thec axis, allowing a close contact between the crystals. These results support the hypothesis that the crystallites would be continuous from the dentino-enamel junction to the surface.
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    Electron microscopy of avian osteopetrosis induced by retrovirus MAV.2-O (1982)
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    Calcified tissue international 34 (1982), S. 382-390 
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    ISSN: 1432-0827
    Keywords: Avian osteopetrosis ; Avian oncornavirus ; Ultrastructure ; Calcification ; Bone cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Diaphyseal tibial bone of 12.5 – 13-day and 19-day-old embryos and 20-day-old hatched chicks infected with retrovirus MAV.2-O were examined by transmission electron microscopy. The viruses were associated with lining osteoblasts and osteocytes. Whereas the infection of the osteoblast layer seemed to be a transient stage, virus association with osteocytes was a constant and main ultrastructural feature. The viruses were found either in the osteoid or in the periosteocytic space of the bone lacunae. They arose from dense cytoplasmic areas located near the cell plasmalemma via a budding process. The newly budded virus particles often had a large tail or a fine stalk-like process lost in the extracellular space. The viruses underwent calcification by deposition of inorganic material and were incorporated in the bone trabeculae. No production of virus was observed in typical osteoclasts with well-differentiated ruffled borders. The viral-induced avian osteopetrosis seemed to result from increased bone deposition through stimulation of osteoblast and osteocyte activities, whereas osteoclastic bone resorption seemed to be undisturbed.
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    Ultrastructural damage due to freezing followed by thawing in shoot meristem and leaf mesophyll cells of tall fescue (Festuca arundinacea Schreb.) (1977)
    Springer
    Planta 134 (1977), S. 159-168 
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    ISSN: 1432-2048
    Keywords: Festuca ; Frost damage ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tillers of Festuca arundinacea Schreb. were subjected to-8°C in a bath of methylated spirits for three-quarters of an hour. They were thawed at room temperature and some material taken from the shoot apical meristem and leaf blade for electron microscopy. Similar material was taken from control plants for electron microscopy. Nine tillers subjected to-8°C and thawed subsequently failed to regrow. Nine control tillers regrew. All the treated meristem cells and about half the treated leaf mesophyll cells were extensively altered. Their nuclei were contracted, organelles were swollen or partly disrupted, plasmalemma and nuclear membranes were broken or absent and vacuoles were sometimes disrupted. Strongly osmiophilic material accumulated in the vicinity of membranes. About half the leaf mesophyll cells differed from the control mesophyll cells only in having more spherosomes and narrower thylakoids. Parallels with other ultrastructural studies of stress damage and the indications the results give of possible primary damaging events are discussed.
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    Early embryogenesis in Tropaeolum majus L.: Diversification of plastids (1976)
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    Planta 133 (1976), S. 15-19 
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    ISSN: 1432-2048
    Keywords: Tropaeolum, Embryogenesis ; Differentiation ; Plastids ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Embryogeny in the nasturtium is characterized by the development of a large, tripartite suspensor and storing cotyledons. A light and electron microscopic study revealed an early diversification of the plastids in the various regions of the suspensor and the embryo proper. Amyloplasts are found in the developing cotyledons of the heart-like embryo, while chloroplasts occur within the meristematic part of the embryo and the adjacent portion of the suspensor. The cells between the meristem and the storing cotyledons display undifferentiated leukoplasts, whereas leukoplasts with an electron-dense matrix occur in the basal cell mass of the embryo-suspensor. Etioplasts develop in several cells of the placental haustorium of the suspensor. The carpel haustorium shows rather undifferentiated leukoplasts, which are transformed into electron-dense plastids during autolysis of the suspensor. This early plastidal differentiation in discussed with respect to its control and functional significance.
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    Unusual cell structures in tumor-like formations of Gracilaria (Rhodophyta) (1976)
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    Archives of microbiology 108 (1976), S. 167-174 
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    ISSN: 1432-072X
    Keywords: Red algae ; Gracilaria verrucosa ; Tumor-like formations ; Ultrastructure ; Viruses ; Endoplasmic reticulum ; Plastids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper deals with electron microscopic observations on cultivated plants of the marine red alga Gracilaria verrucosa which developed simple galls; also sea collected material, without galls, had been studied. The galls showed unusual but characteristic cell structures, caterpillar-like bodies, containing rows of fusiform bodies. These were found mostly in the cytoplasm near the plastids, in one case connected with the endoplasmic reticulum, occasionally even inside the nucleus, and are described here, as far as we know, for the first time. It does not seem probable that the caterpillar-like bodies represent mitochondria or bacteria, but the hypothesis that fusiform bodies are related to virus-like structures is discussed. The normal tissues as well as the gall tissue of the laboratory plants contained, besides plastids typical for the red algae, another type of plastids characterized by tubular thylakoids.
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    Mycoparasitic relationships (1977)
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    Archives of microbiology 111 (1977), S. 207-224 
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    ISSN: 1432-072X
    Keywords: Host-parasite relationships ; Ultrastructure ; Papillae ; Infection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mode of attack and the infection structures of the necrotrophic mycoparasite, Pythium acanthicum, as well as the responses of various fungal hosts to parasitism were studied using both electron and light microscopy. Many taxonomically distinct fungal hosts were used, though Phycomyces blakesleeanus, Pythium aphanidermatum, Rhizoctonia solani and a basidiomycete identified as Corticium sensu lato were studied in greatest detail. Parasitism was by direct penetration of the fungal host without appressorium formation by the parasite. The host's cells responded to contact by P. acanthicum by forming papillae. The morphological features of the papillae varied with the particular host. In P. blakesleeanus they were comprised of vesicles and segments of cytoplasm entrapped in a fibrillo-granular matrix, while in R. solani and the Corticium basidiomycete they contained considerable amounts of electron-opaque and electron-translucent material. Evidence for both mechanical and enzymatic penetration of the host fungi by the parasite are presented. Details of host wall and septum penetration by the parasite are presented using time-lapse light microscopy with in vivo systems. Many of these stages of parasitism were examined ultrastructurally. Some comparisons of these mycoparasitic relationships are discussed in relation to what is known from the literature about phytoparasitic interactions.
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    Gametangial development in Allomyces macrogynus (1977)
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    Archives of microbiology 113 (1977), S. 163-172 
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    ISSN: 1432-072X
    Keywords: Allomyces ; Phycomycete ; Ultrastructure ; Gametangial differentiation ; Autophagy ; Gamma bodies ; Multivesicular bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ultrastructure of gametangial development in Allomyces macrogynus was determined from longitudinal sections of gametophytic hyphae at stages of differentiation from vegetative apices at time zero to fully cleaved gametangia at about 150 min. Whereas vegetative hyphae show an apical clustering of mitochondria, cytoplasmic vesicles and microtubules, this arrangement was sharply altered in early development. Mitochondria were evenly redistributed, apical vesicles and microtubules disappeared, and autophagic vacuoles became prominent. Subsequently, electron-dense granules and microbody/lipid droplet complexes became evident and later, during gamete cleavage, developed into gamma bodies and side-body complexes respectively. Meanwhile cytoplasmic vesicles were involved in exit papilla formation. The significance of autophagic vacuoles and multivesicular bodies is discussed.
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    Dorsal-ventral differentiation in Simonsiella and other aspects of its morphology and ultrastructure (1977)
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    Archives of microbiology 113 (1977), S. 197-204 
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    ISSN: 1432-072X
    Keywords: Gliding bacterium ; Simonsiella ; Oral cavity ; Electron microscopy ; Morphology ; Dorsal-ventral differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the aerobic, Gram-negative multicellular-filamentous bacteria of the genus Simonsiella were investigated by scanning and transmission electron microscopy. The flat, ribbon-shaped, multicellular filaments show dorsal-ventral differentiation with respect to their orientations to solid substrata. The dorsal surface, orientated away from the substrate, is convex and possesses an unstructured capsule. The ventral surface, on which the organisms adhere and glide, is concave and has an extracellular layer with fibrils extending at right angles from the cell wall. The cytoplasm in the ventral region contains a proliferation of intracytoplasmic membranes and few ribosomes in comparison to the cytoplasm in other parts of the cell. Centripetal cell wall formation is asymmetrical and commences preferentially in the ventral region. Quantitative differences in morphology and cytology exist among selected Simonsiella strains. Functional aspects of this dorsalventral differentiation are discussed with respect to the colonization and adherence of Simonsiella to mucosal squamous epithelial cells in its ecological habitat, the oral cavities of warm-blooded vertebrates.
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    Two unicellular cyanobacteria which reproduce by budding (1977)
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    Archives of microbiology 115 (1977), S. 249-257 
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    ISSN: 1432-072X
    Keywords: Chamaesiphon spp. ; Cyanobacteria ; Reproduction by budding ; Ultrastructure ; Nutritional properties ; DNA base composition ; Fatty acid composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of unicellular cyanobacteria which reproduce exclusively by budding are described and assigned to genus Chamaesiphon.
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    Methanogenium, a new genus of marine methanogenic bacteria, and characterization ofMethanogenium cariaci sp. nov. andMethanogenium marisnigri sp. nov. (1979)
    Springer
    Archives of microbiology 121 (1979), S. 147-153 
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    ISSN: 1432-072X
    Keywords: Methanogenium cariaci ; Methanogenium marisnigri ; Marine methanogenic bacteria ; Ultrastructure ; TaxonomyMethanogenium gen. nov.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
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    An electron microscopic study on the mating tube formation in the heterobasidiomycete Tremella mesenterica (1980)
    Springer
    Archives of microbiology 128 (1980), S. 215-221 
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    ISSN: 1432-072X
    Keywords: Mating tube ; Microtubule ; Tremella ; Ultrastructure ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ultrastructure of the mating tube formed in yeast haplont of the heterobasidiomycete Tremella mesenterica was studied by electron microscopy. Cell wall of the mating tube emerged as evagination of the inner layers, rupturing outer layers of the mother cell wall. Comparison with budding cells suggested that the tube emergence place at bud scar and the process of tube emergence was the same as that of bud emergence. Electron transparent vesicles of 0.1 μm diameter were scattered in the cytoplasm of the mating tube. Nucleus-associated organelle was located at one side of the nuclear envelope which extended towards the mating tube. A few microtubules were detected in the mating tube, but their association with a nucleus was not clear. The cytoplasmic structure of the mating tube was discussed in comparison with that of hyphae of the filamentous fungi.
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    Ultrastructural events and kinetics of microcyst germination in the myxomycete Didymium iridis (1981)
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    Archives of microbiology 128 (1981), S. 384-389 
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    ISSN: 1432-072X
    Keywords: Didymium iridis ; Microcyst ; Excystment ; Germination ; Ultrastructure ; Mycetozoa ; Myxomycetes ; Myxamoeba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microcysts of the myxomycete Didymium iridis were induced to excyst by transfer to 5mM potassium phosphate buffer. After 1 h in suspension, 90% of the microcysts had germinated into myxamoebae distinguishable by phase contrast microscopy and staining with Lugol's iodine. Both pH and osmolarity affected the kinetics of excystment. The rate and extent of excystment were decreased by cycloheximide but remained unaffected by actinomycin D, suggesting a requirement for protein synthesis but not RNA synthesis. Initially, the outer wall layers separated from the inner layer, which gradually expanded and loosened. The protoplast rehydrated and reverted to a vegetative morphology. Excysting cells were characterized by nucleolar inclusions, changes in the nuclear envelope and plasma membrane, appearance of ringed cisternal elements and microbodies in the cytoplasm, and formation of a densely fibrous zone adjacent to the site of emergence. Excysting populations have been classified into characteristic stages: mature, initiated, swollen, and pre-emergent microcysts.
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    Ultrastructure of the cyanobacterium,Mastigocladus laminosus (1982)
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    Archives of microbiology 133 (1982), S. 11-19 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Mastigocladus laminosus ; Fischerella ; True branching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the thermophilic cyanobacteriumMastigocladus laminosus were examined by scanning and transmission electron microscopy. Mature cultures consisted of relatively old, wide filaments that branched frequently to form younger, thinner filaments. The cells of the younger filaments had a consistently cylindrical morphology, while those of older filaments were rounded and pleomorphic. The internal ultrastructure of the cells depended somewhat on their age. As young cells became larger and wider, their thylakoids underwent slight rearrangement and spread out toward the center of the cytoplasm. Polyphosphate bodies, carboxysomes (polyhedral bodies), and lipid-body-like structures increased in number as the cells aged, but ribosomes and cyanophycin granules were depleted. Cell division involved septum formation followed by ingrowth of the outer membrane and sheath. Cells in older filaments were separated from each other by a complete layer of sheath material. Septum formation in older cells was also seen to occur parallel to the long axis of the filament, thereby confirming that true branching took place.
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    Isolation and characterization of a new coccoid methanogen, Methanogenium tatii spec. nov. from a solfataric field on Mount Tatio (1984)
    Springer
    Archives of microbiology 137 (1984), S. 308-315 
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    ISSN: 1432-072X
    Keywords: Methanogenium tatii ; Ultrastructure ; Physiology ; Glycoproteins ; DNA-DNA Homology ; Taxonomy ; Archaebacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new coccoid methanogen, Methanogenium tatii, was isolated and characterized. The mesophilic isolate can grow on and produce methane from H2:CO2 and formate. For growth acetate is strictly required. The cell shape, the G+C content of 54 mol% and DNA-DNA homology data suggest it to be a Methanogenium species.
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    Fine structure of the knobby spore type of Streptomyces torulosus (1984)
    Springer
    Archives of microbiology 138 (1984), S. 229-232 
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    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces torulosus ; Morphology ; Ultrastructure ; Verrucate spores ; Knobby ornamentation ; Sheath
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The type strain of Streptomyces torulosus Lyons and Pridham (1971) was studied by scanning- and transmission electron microscope. Spore chains were formed in spirals by aerial mycelium. The spores were connected by nozzles in which small channels could be observed. The knobby ornamentations of the spores arised on a thin fibrous sheath, enveloping the spore chains. These irregular blunt projections, called knobs, had varying diameters of 100 to 250 nm. The base of the knob, consisting of globose to flattened electron dense material, was sitting directly on the sheath. It was covered by several small vesicles of the same material. Each hollow vesicle beared a thin bowlshaped shell of electron transparent material. In general, the cupular bowls and their supporting vesicles became easily depressed on their base, but not detached from the surface of the spores. This type of knobby spore ornamentation was suggested to be designated as a verrucate spore type.
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    The effects of nitrogen limitation on the ultrastructure of the cyanobacterium Agmenellum quadruplicatum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 204-212 
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    ISSN: 1432-072X
    Keywords: Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
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    La paroi cellulaire de Coelastrum (Chlorophycées) (1975)
    Springer
    Archives of microbiology 102 (1975), S. 95-101 
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    ISSN: 1432-072X
    Keywords: Coelastrum ; Chlorococcales ; Chlorophyta ; Ultrastructure ; Cell Wall ; Tubules ; Bristles ; Polymorphism ; Buoancy ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé La paroi cellulaire de Coelastrum est généralement composée de trois couches. La couche la plus externe a été plus particulièrement étudiée. Elle est composée de tubules dressées, et porte souvent de longues fibrilles dont le rôle serait de stabiliser l'algue dans son milieu. La morphologie de la paroi cellulaire peut se modifier en fonction du milieu.
    Notes: Abstract The cell wall of Coelastrum is usually composed of three layers. The outermost layer was studied most extensively. It consists of erect tubules which often bear long bristles whose function may be to stabilize the algae in its environment. The cell wall can modify its morphology according to the environment.
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    Effects of diazepam on photosynthesis, respiration, rubidium uptake, and finestructure of Scenedesmus obliquus in synchronous cultures (1975)
    Springer
    Archives of microbiology 102 (1975), S. 129-137 
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    ISSN: 1432-072X
    Keywords: Diazepam ; Benzodiazepines ; Scenedesmus ; Ultrastructure ; Photosynthesis ; Respiration ; Rubidium Uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of diazepam (Valium) on photosynthesis, chlorophyll/photosynthesis ratios, respiration, uptake of rubidium ions, and ultrastructure of Scenedesmus obliquus synchronized by a light-dark regimen of $$14:\overline {10}$$ hrs were determined. 80 and 160 μM diazepam, added to the nutrient medium at the start of the light-dark change (i.e., start of the cell cycle) gradually reduced rates of photosynthesis below the initial rates from the beginning of the experiment. Contents of chlorophyll, however, remained nearly unaffected. Consequently, the diazepam-treated cells had a higher chlorophyll/photosynthesis ratio—also with regard to respiration in order to calculate the gross photosynthesis. The occurrence of photorespiration cannot be assumed. The net influx or rubidium was slightly reduced by 100 μM diazepam 0.5 and 2.0 hrs after the start of the cell cycle and was strongly inhibited after 5 to 14 hrs. 80 and 160 μM diazepam caused separation of thylakoids, formation of giant mitochondria and enlargement of vacuoles. The results are discussed and it is finally suggested that diazepam acts on different membrane systems. Furthermore an ATP deficiency cannot be excluded.
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    Ultrastructural changes occurring during germination and outgrowth of spores of the thermophile Bacillus acidocaldarius (1975)
    Springer
    Archives of microbiology 102 (1975), S. 155-161 
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    ISSN: 1432-072X
    Keywords: Bacillus acidocaldarius ; Spores ; Germination ; Thermophile ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spores of the thermophilic, acidophilic, Bacillus acidocaldarius were covered by a thick outer coat and a laminated inner coat (5.5 nm periodicity). Small membranous vesicles were present in the spore core and they disappeared as germination proceeded. After depolymerization of the cortex, and a 30% increase in spore diameter, a localized gap appeared in the laminated inner coat only. This inner coat gap was narrow and could be the whole length of the spore. The germ cell appeared to grow, or to be pushed towards the inner coat gap, at which stage the outer coat disappeared in the same localized area. As the vegetative cell grew out the spore coat fell away, with loose cortical material still attached to it. The young germ cell developed a large spherical electron dense inclusion body in the cytoplasm, at the same time as the ribosomal and nuclear areas became distinct.
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    An ammonia-oxidizing bacterium, Nitrosovibrio tenuis nov. gen. nov. sp. (1976)
    Springer
    Archives of microbiology 108 (1976), S. 105-111 
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    ISSN: 1432-072X
    Keywords: Ammonia oxidizing bacterium ; Nitrosovibrio tenuis ; Isolation ; Morphology ; Ultrastructure ; Physiology ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ammonia-oxidizing, autotroph growing, slender, curved rod was isolated from the soil of Hawaii. It is well distinguishable from any other nitrifying bacteria thus far described by their morphology. The cells are 1.1–3.0 μm long and 0.3–0.4 μm wide. They are motile by means of 1–4 subpolar to lateral flagella. In contrast to most of the ammonia-oxidizing bacteria the isolated vibrio is void of an extensive cytomembrane system. To categorize this not yet described species we propose to create the new genus Nitrosovibrio and to classify the isolated strain as Nitrosovibrio tenuis.
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    Micromorphology of Gram-negative hydrogen bacteria (1977)
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    Archives of microbiology 114 (1977), S. 93-100 
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    ISSN: 1432-072X
    Keywords: Ultrastructure ; Micromorphology ; Gram-negative hydrogen bacteria ; Flagellation ; Flagellar fine structure ; Pili
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cell morphology, the arrangement and fine structure of flagella and the piliation of the following Gram-negative aerobic hydrogen bacteria have been studied: Alcaligenes eutrophus, Alcaligenes paradoxus, Alcaligenes ruhlandii, Pseudomonas flava, Pseudomonas pseudoflava, Pseudomonas palleronii, Pseudomonas facilis, Aquaspirillum autotrophicum, Paracoccus denitrificans, Corynebacterium autotrophicum, and strains MA 2 and SA 35. The identity of the bacteria was examined by their substrate spectra and type of flagellation. Three types of flagellar fine structure were differentiated. The presence of pili was noted in strains of Alcaligenes paradoxus, Pseudomonas flava, P. pseudoflava, P. palleronii, and P. facilis.
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    The effect of aminopterin (4-amino folic acid) on growth and cell division of fermentative versus oxidative yeasts (1977)
    Springer
    Archives of microbiology 113 (1977), S. 293-302 
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    ISSN: 1432-072X
    Keywords: Aminopterin ; Saccharomyces cerevisiae ; Polyploid ; Oxidative-fermentative yeast ; Ultrastructure ; Bioassay ; Synchrony
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a related brewing study detailed characteristics of fermentations displaying effective yeastaminopterin interaction were presented. Fermentative yeast types (certain Saccharomyces species and Selenotila intestinalis) proved effective aminopterin reactors whereas oxidative yeasts (certain Candida, Cryptococcus, Pichia, Rhodotorula, Saccharomyces, and Trigonopsis species) proved ineffective reactors. In general effective reactors were polyploids characterized by the lack of film or pellicle formation and ineffective reactors the opposite. In stationary fermentations the Fleischmann 139 strain of S. cerevisiae proved a fair reactor. When aerated it proved an ineffective reactor and aminopterin or products there-of stimulated growth. Conversely aeration enhanced aminopterin activity of effective reactor yeasts. The positive effect of biotin on aminopterin activity and the negative effect of yeast extract, L-asparagine, adenine and thymine is shown and compared and contrasted with earlier reported studies. These findings supported by outside data suggest that oxidative yeasts (and bacteria) can readily elicit enzymes capable of inactivating aminopterin whereas fermentative types are lacking in this capability. Finally that past yeast-aminopterin studies were conducted with oxidative yeast types. Advantages of effective aminopterin reactor yeasts to be published elsewhere include improved ultrastructure using KMnO4−OsO4 fixation, a yeast bioassay procedure for detecting aminopterin in plasma and urine, and cell synchronization.
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    A comparative ultrastructural study of the ascospores of some Saccharomyces and Kluyveromyces species (1979)
    Springer
    Archives of microbiology 121 (1979), S. 53-59 
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    ISSN: 1432-072X
    Keywords: Saccharomyces ; Kluyveromyces ; Ultrastructure ; Ascospore wall ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three types of structure of the ascospore wall were found among the haploid Saccharomyces species examined: a warty wall (S. rouxii), a smooth wall with a single electron-light inner layer (S. bailii) and a smooth wall with a double light inner layer (S. montanus, S. florentinus). The latter type also occurred in Kluyveromyces thermotolerans and K. waltii. In K. fragilis spores the wall had a single light inner layer. The taxonomic implications of these findings were discussed.
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    Arthrobacter P 1, a fast growing versatile methylotroph with amine oxidase as a key enzyme in the metabolism of methylated amines (1981)
    Springer
    Archives of microbiology 129 (1981), S. 72-80 
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    ISSN: 1432-072X
    Keywords: Arthrobacter ; Facultative methylotroph ; Amine oxidase ; Catalase ; RuMP cycle of formaldehyde fixation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3.) activity. Glucose- or choline-grown cells lacked this enzyme. Oxidation of primary amines by the enzyme resulted in the formation of H2O2; as a consequence high levels of catalase were present in methylamine-and ethylamine-grown cells. The significance of catalase in vivo was demonstrated by addition of 20 mM aminotriazole (a catalase inhibitor) to exponentially growing cells. This completely blocked growth on methylamine whereas growth on glucose was hardly affected. Cytochemical studies showed that methylamine-dependent H2O2 production mainly occurred on invaginations of the cytoplasmic membrane. Assimilation of formaldehyde which is generated during methylamine oxidation was by the FBP variant of the RuMP cycle of formaldehyde fixation. The absence of NAD-dependent formaldehyde and formate dehydrogenases indicated the operation of a non-linear oxidation sequence for formal-dehyde via hexulose phosphate synthase. Enzyme profiles of the organism grown on various substrates suggested that the synthesis of amine oxidase, catalase and the enzymes of the RuMP cycle is not under coordinate control.
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    Cell wall enzymatic lysis of the yeast form of Pullularia pullulans and wall regeneration by protoplasts (1975)
    Springer
    Archives of microbiology 104 (1975), S. 271-277 
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    ISSN: 1432-072X
    Keywords: Protoplasts ; Regeneration ; Wall Structure ; Pullularia ; Ultrastructure ; Membrane Splitting ; Aberrant Tubes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During the process of degradation of the cell wall of the yeast form of Pullularia pullulans by the lytic system of Micromonospora chalcea samples were withdrawn at different times and observed under phase contrast and electron microscope. The progressive lysis of the walls reveals a fibrillar component inside the apparently amorphous wall. Freeze etched preparations of cells during the formation and regeneration of protoplasts show that the cellular membrane is split and this method allows the smooth external face of the membrane and other internal face covered by particles to be seen. The fact that the smooth face of the membrane is only visible during the preparation or the regeneration of protoplasts and very rarely when intact cells are fractured, suggests a strong adherence between cell wall and this external layer of the membrane. During the regeneration which takes place as in most of the yeasts and moulds, a special study of the extension of the cell wall is made and a possible mechanism for this extension of the regenerated cell wall is proposed.
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    Changes of the cytoplasmic ultrastructure during development of sclerotia in Claviceps purpurea (Fr.) Tul. (1980)
    Springer
    Archives of microbiology 125 (1980), S. 251-257 
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    ISSN: 1432-072X
    Keywords: Claviceps purpurea ; Ultrastructure ; Development ; Sclerotium ; Oleosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The development of sclerotia of Claviceps purpurea was investigated by light and electron microscopy. During the first days after infection sterigma and conidiospores are formed. The spores show a moderately developed vacuolar system, they are thick walled and contain about 20% lipid (related to the cell volume) embedded in glycogen. The sterigma are cylindrical unicellular hyphae with electron dense cytoplasm and isolated strongly contrasted lipid droplets. In maturing sclerotia the hyphae become septated with increasingly thick cell walls and a large lipid content. The lipid forms small droplets in young cells, while in the mature sclerotium it occurs in the form of very large drops, occupying the major part of the cell. Simultaneously the composition of the lipid is changed. The mature cells have several nuclei. They are partially connected by osmiophilic substances, forming a network of intercellular spaces.
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    Ultrastructure of infection of Cokeromyces recurvatus by Piptocephalis unispora (Mucorales) (1976)
    Springer
    Archives of microbiology 109 (1976), S. 277-288 
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    ISSN: 1432-072X
    Keywords: Ultrastructure ; Mucorales ; Piptocephalis ; Mycoparasitism ; Cokeromyces ; Yeastphase ; Appressorium ; Infection peg ; Penetration ; Haustorium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Infection of the mucoraceous host Cokeromyces recurvatus by Piptocephalis unispora was studied ultrastructurally, using a new technique involving yeast-phase cells of the host to obtain large numbers of infection sites for thin-sectioning. Morphologically, the haustorial apparatus was similar to that of fungi parasitic on higher plants, and comprised an appressorium, a neck region with a collar and a neck ring, and a lobed region surrounded by a sheath matrix enclosed in an extra-haustorial membrane. Penetration of the host by the infection peg probably involved both enzymatic degradation and physical pressure. Reaction of the host to infection is described and the results related to the theory of host infection by haustorial fungal parasites.
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    Isolation of a moderate halophilic ammonia-oxidizing bacterium, Nitrosococcus mobilis nov. sp. (1976)
    Springer
    Archives of microbiology 107 (1976), S. 277-282 
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    ISSN: 1432-072X
    Keywords: Nitrosococcus mobilis ; Ammonia oxidizing bacterium ; Morphology ; Ultrastructure ; Physiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ammonia-oxidizing bacterium was isolated from a sample of brackish water (North Sea, Harbour of Husum). It is a motile large coccus 1.5–1.7 μm in diameter. The extensive cytomembrane system occurring as flattened vesicles in the peripheral region of the cytoplasm and as intrusions into the center of the cytoplasm is to be emphasized as a characteristic mark of identification. The lithoauto-trophically growing bacterium turned out to be an obligate halophile. Because of its physiological and morphological properties, we assigned it to the genus Nitrosoccus and propose the name Nitrosococcus mobilis.
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    Origin of sclerotia-like cells in submerged Claviceps purpurea producing clavine alkaloids (1976)
    Springer
    Archives of microbiology 107 (1976), S. 321-327 
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    ISSN: 1432-072X
    Keywords: Claviceps purpurea ; Saprophytic ; Clavine alkaloids ; Ultrastructure ; Extended hyphae ; Blastospores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ultrathin sectioning of submerged mycelium of Claviceps purpurea Tul. producing clavine alkaloids revealed yeast-like budding resulting in asexual sporesblastospores. These deciduous spores were born by extended hyphal cells and retained the same ultrastructure of cell organelles. Both the extended hyphae and the blastospores resembled the cells of ergot sclerotial tissue. A surface culture of C. purpurea Tul. producing no alkaloids was used as a reference.
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    Micromorphology of Gram-negative hydrogen bacteria (1977)
    Springer
    Archives of microbiology 114 (1977), S. 101-110 
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    ISSN: 1432-072X
    Keywords: Ultrastructure ; Micromorphology ; Gram-negative ; Hydrogen bacteria ; Cell envelope ; Cytoplasmic inclusions ; Membranes ; Mesosomes ; Glycogen ; Poly-β-hydroxybutyrate ; Cell wall types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The fine structure of the cell envelope, of membrane systems and of cytoplasmic inclusions of Gram-negative aerobic hydrogen bacteria has been studied. The results have been tabulated, and three main groups could be recognized: Group 1: Alcaligenes eutrophus, A. paradoxus, A. ruhlandii, Pseudomonas facilis, P. flava, P. pseudoflava, P. palleronii, and Aquaspirillum autotrophicum; Group 2: “Corynebacterium” autotrophicum and strains MA 2 and SA 35; Group 3: Paracoccus denitrificans. Special structures related to the chemoautotrophic way of life of the hydrogen bacteria were not observed.
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    Disappearence of the intracytoplasmic membranes inRhodopseudomonas sphaeroides (1978)
    Springer
    Archives of microbiology 117 (1978), S. 293-295 
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    ISSN: 1432-072X
    Keywords: Rhodopseudomonas sphaeroides ; Intracytoplasmic membranes ; Membranes ; Ultrastructure ; Bacteriochlorophyll ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic bacterium,Rhodopseudomonas sphaeroides, can be grown phototrophically (light, anaerobiosis), of chemotrophically (dark, aerobiosis). In the first case, it contains intracytoplasmic membranes with photosynthetic pigments. When shifted from phototrophy to chemotrophy these membranes disappear in an unknown fashion. In the present experiment, samples were taken for electron microscopy, cell density and bacteriochlorophyll determinations after shift from phototrophy to chemotrophy. The density of intracytoplasmic vesicles was measured on micrographs. During the first 2h growth is very slow and the ultrastructure remains unaltered. As growth resumes, the vesicles disappear at a rate which implies that they are not incorportated into the cytoplasmic membrane, nor actively digested, but remain intact and become increasingly diluted in the cytoplasm as the culture grows. The size of the vesicles was estimated to about 500 Å. The number of vesicles in phototrophically grown cells was calculated to about 575 per cell, and after 6h chemotrophic growth to about 100. The areas of the cytoplasmic and intracytoplasmic membranes are roughly calculated.
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    Sporogenesis in Streptomyces melanochromogenes (1978)
    Springer
    Archives of microbiology 118 (1978), S. 309-316 
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    ISSN: 1432-072X
    Keywords: Streptomyces melanochromogenes ; Sporogenesis ; Formation of sporulation septum ; Delimitation, separation, and release of spores ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mode of spore differentiation in a strain of Streptomyces melanochromogenes was followed by analysis of ultrathin sections of sporulating aerial hyphae at various stages of sporogenesis. A special accent was laid on the formation of the sporulation septum and its alterations in the course of spore delimitation and separation. Distinct differences in formation and substructure have been observed between the cross walls of vegetative hyphae and the sporulation septa. Cross walls of vegetative hyphae are formed in a way typical for Gram-positive bacteria by a centripetal annular ingrowth of cytoplasmic membrane, on which wall material immediately is deposited. The development of the sporulation septa is characterized by the accumulation of amorphous material in addition to the newly synthesized wall layer inside the invaginating cytoplasmic membrane. This amorphous septal material will later be decomposed presumably by two lytic systems which cause the separation of the spores. The central region of the finished sporulation septum is perforated by microplasmodesmata. Spores are released by a break down of the surface sheath. The complete spores are enveloped by a twolayered cell wall and the spiny surface sheath.
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    Capnocytophaga: New genus of Gram-negative gliding bacteria. II. Morphology and ultrastructure (1979)
    Springer
    Archives of microbiology 122 (1979), S. 17-27 
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    ISSN: 1432-072X
    Keywords: Gliding bacteria ; CO2-requiring ; Periodontal disease ; Gram-negative ; Ultrastructure ; Capnocytophaga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gram-negative, anaerobic gliding bacteria were isolated from normal supragingival plaque and from periodontal lesions. Isolates could be divided into two size classes: small 2.4–4.2 μm×0.38–0.5 μm and large 4.8–5.8 μm×0.42–0.6 μm cells. The outer membrane was either loose-fitting and wavy, or taut, and of variable thickness. An electron-dense fuzz was discernible on several of the isolates. The periplasmic region was of variable electron-density. The genus Capnocytophaga has been proposed for these organisms based on morphological and cultural characteristics.
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    Membrane-bound nitrite oxidoreductase of Nitrobacter: evidence for a nitrate reductase system (1984)
    Springer
    Archives of microbiology 140 (1984), S. 153-158 
    Details
    ISSN: 1432-072X
    Keywords: Nitrobacter hamburgensis ; Nitrite oxidoreductase ; Nitrate reductase ; Molybdenum iron-sulfur protein ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrite oxidoreductase, the essential enzyme complex of nitrite oxidizing membranes, was isolated from cells of the nitrifying bacterium Nitrobacter hamburgensis. The enzyme system was solubilized and purified in the presence of 0.25% sodium deoxycholate. Nitrite oxidoreductase oxidized nitrite to nitrate in the presence of ferricyanide. The pH optimum was 8.0, and the apparent K m value for nitrite amounted to 3.6 mM. With reduced methyl-and benzylviologen nitrite oxidoreductase exhibited nitrate reductase activity with an apparent K m value of 0.9 mM for nitrate. NADH was also a suitable electron donor for nitrate reduction. The pH optimum was 7.0. Treatment with SDS resulted in the dissociation into 3 subunits of 116,000, 65,000 and 32,000. The enzyme complex contained iron, molydbenum, sulfur and copper. A c-type cytochrome was present. Isolated nitrite oxidoreductase is a particle of 95±30 Å in diameter.
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    The ultrastructure and development of the colonial sheath of Microcystis marginata (1975)
    Springer
    Archives of microbiology 106 (1975), S. 209-214 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Colonial sheath ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The colonial sheath of Microcystis marginata has a definite structure as seen by light and electron microscopy, consisting of a relatively smooth inner surface and densely packed, long fibrils on the outer surface. The sheath initially forms around the single cell and expands by continual deposition of sheath material to accomodate the synchronously dividing cells of the colony.
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    Growth of Nitrobacter in the presence of organic matter (1976)
    Springer
    Archives of microbiology 108 (1976), S. 305-312 
    Details
    ISSN: 1432-072X
    Keywords: Nitrobacter agilis ; Chemoorganotrophic growth ; Acetate ; Formate ; Pyruvate ; Yeast extract-peptone ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. After a resting period of up to 6 months cells of Nitrobacter agilis grow with acetate, formate, and pyruvate as carbon and energy source. Yeast extract and peptone were added to supply the organism with nitrogen and to meet possible vitamin requirements. 2. The length of the growth period depends on the substrate; it increases according to the following sequence: pyruvate, formate, acetate. The highest growth yield is observed with pyruvate, the lowest with formate. 3. O2 consumption is increased in the presence of substrates as compared to endogenous respiration. With pyruvate and acetate twice as much O2 is consumed, with formate 7 times, with yeast extractpeptone 10 times as much. 4. The ability of nitrite oxidation is largely preserved, except in cells grown with acetate or pyruvate in the presence of 0.015% yeast extract and peptone. Such cells have nearly no cytochrome a 1. Accordingly, the cytochrome spectra of nitrite oxidizers grown under chemoorganotrophic and lithoautotrophic conditions coincide qualitatively. 5. The nitrite oxidizing system is inducible. It is induced by nitrite but also by substances present in yeast extract and peptone. Cells grown on acetate and yeast extract and peptone (0.015%) require 3–4 weeks before they regain the ability to grow with nitrite. Cells grown chemoorganotrophically with the same substrates and yeast extract and peptone (0.15%) start growing with nitrite as energy source without a lag. 6. Cell size and form, distribution of storage materials, order and fine structure of double membranes are correlated with growth conditions.
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    Synaptonemal complexes in antheridia of Achlya ambisexualis E87 (1977)
    Springer
    Archives of microbiology 112 (1977), S. 311-313 
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    ISSN: 1432-072X
    Keywords: Achlya ; Synaptonemal complexes ; Oömycetes ; Ultrastructure ; Gametangial meiosis ; Mycology ; Antheridium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This is the first report of longitudinal sections of synaptonemal complexes in oömycetous fungi. These indicators of meiosis were observed in antheridial nuclei of Achlya ambisexualis E87. They were attached to a platelike structure at the inner membrane of the nuclear envelope. The lateral elements were separated from each other by an average distance of 160 nm. These results provide new ultrastructural evidence for gametangial meiosis in Oömycetes.
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    Ultrastructural study of microcyclic macroconidiation in Neurospora crassa (1978)
    Springer
    Archives of microbiology 116 (1978), S. 279-288 
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    ISSN: 1432-072X
    Keywords: Neurospora crassa ; Macroconidia ; Microcycle ; Heat ; Ultrastructure ; Nucleolus ; Proconidia ; Septa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heat-shock of macroconidia of Neurospora crassa at 46°C followed by shift-down to 25°C determines premature conidiogenesis. The nuclei and cytoplasm of heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. In the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are peripherally spread. A few such vesicles are later seen lining the initially simple septum separating the proconidial units into conidia. The doubling of this interconidial septum is surface viewn as a thick annulus. Disarticulation of the conidial units intervenes along a septal furrow of electroluscent material. Interconidial continuity through the septal pores is transiently insured by a connective which is ruptured for final liberation of the conidia.
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    Polyhedral inclusion bodies in cells of nitrosomonas spec (1977)
    Springer
    Archives of microbiology 112 (1977), S. 69-72 
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    ISSN: 1432-072X
    Keywords: Nitrosomonas spec ; Ammonia oxidizing bacterium ; Polyhedral inclusion bodies ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyhedral inclusion bodies were observed in cells of a Nitrosomonas species. They were present in growing cells as well as in resting cells. In thin sections their size was about 130 nm in growing cells and about 185 nm in diameter in resting cells. The bodies were commonly located in the nucleoplasm. They appeared to be bounded by a nonunit membrane and had a granular substructure. In thin sections about 70% of the exponentially grown cells and about 20% of the resting cells of the investigated strain showed 1–7 respectively 1–3 inclusion bodies.
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    Ultrastructure of tuberculate spores in Streptomyces thermoviolaceus (1983)
    Springer
    Archives of microbiology 134 (1983), S. 295-298 
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    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
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    Chroococcus S24 and Chroococcus N41 (cyanobacteria): morphological, biochemical and genetic characterization and effects of water stress on ultrastructure (1983)
    Springer
    Archives of microbiology 135 (1983), S. 81-90 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
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    Behavior genetics of choice of oviposition sites inDrosophila melanogaster. I. Genetic variability and analysis of behavior (1980)
    Springer
    Behavior genetics 10 (1980), S. 105-120 
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    ISSN: 1573-3297
    Keywords: Drosophila melanogaster ; choice of oviposition site ; strain difference ; site discrimination ; egg insertion ; selection ; wild type
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Females ofDrosophila melanogaster were given a choice of oviposition site either on the surface of the medium or on the surface of paper positioned vertically on the medium. A significant difference was seen in the proportion of eggs deposited on the paper among wild strains of different geographic origins. Bidirectional selection for oviposition on these two sites was effective. These selected lines were examined under various conditions to determine the factors involved in this site selection for oviposition. The lines that chose medium laid eggs only on substrates into which egges could be inserted. The lines preferring paper showed no strict requirement for burying their eggs. Tarsal sensillae were involved in site discrimination.
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    Relative male age, fertility, and competitive mating success inDrosophila melanogaster (1980)
    Springer
    Behavior genetics 10 (1980), S. 163-170 
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    ISSN: 1573-3297
    Keywords: Drosophila melanogaster ; mating success ; male fertility ; male age ; female choice experiments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Female choice experiments were used to investigate the effect of relative male age on mating success inD. melanogaster. Experiments were conducted with a Canton-S (CS) strain, in which two virgin males of different ages (2, 4, or 8 days old) were offered to virgin females. Older males were found to be more successful under competitive conditions. In another group of experiments, vermilion (v) males of different ages competed with CS males of different ages. The competitive success ofv males was found to increase with their relative age. Male fertility at 2, 4, and 8 days of age was documented for both male genotypes mated with CS females. CS males fathered more offspring per copulation thanv males, and the fertility of all males was found to increase with age. Discussion focuses on the changes in male mating success and fertility with age and genotype.
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    Nutritional control of xanthine dehydrogenase. II. Effects on xanthine dehydrogenase and aldehyde oxidase of culturing wild-type and mutant Drosophila on different levels of molybdenum (1975)
    Springer
    Biochemical genetics 13 (1975), S. 53-64 
    Details
    ISSN: 1573-4927
    Keywords: aldehyde oxidase ; xanthine dehydrogenase ; Drosophila melanogaster ; molybdenum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two new mutants, deficient in aldehyde oxidase and xanthine dehydrogenase, have been isolated from a wild-type stock of Drosophila melanogaster and have been provisionally termed lxd c and lxd d, respectively, as both mutants appear to be allelic with lxd (low xanthine dehydrogenase). An analysis has been made of the effects of dietary molybdenum on lxd, lxd c, lxdd, lao (low aldehyde oxidase), mal (maroon-like eye color), and pac (Pacific) wild-type flies. On the lower dietary levels of 10 −3 M and 10 −2 M molybdenum, increases in specific activity of both enzymes were observed only in lxd. Furthermore, two- to three-fold increases in specific activity of both enzymes occurred in all strains, except mal, when cultured on 5×10 −2 M molybdenum. The lxd and lxd c strains failed to survive on this high concentration of the ion. Similar concentrations of molybdenum had no effect in vitro. An extra electrophoretic band of xanthine dehydrogenase was observed on polyacrylamide gel from extracts of wild-type flies cultured on certain levels of molybdenum, but its appearance was not always correlated with the increases in specific activity.
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    The size of poly(A)-containing RNAs in Drosophila melanogaster embryos (1976)
    Springer
    Biochemical genetics 14 (1976), S. 357-371 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; poly(A)-containing RNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The size range of poly(A)-containing RNA from Drosophila melanogaster embryos has been estimated by hybridization with 3H-labeled poly(U) and subsequent fractionation on sucrose gradients. The median size of nuclear poly(A)-containing RNA is about 30 S (6000 nucleotides), and the median size of cytoplasmic poly(A)-containing RNA is about 17 S (1800 nucleotides). The relationship of these sizes to messenger RNA needed to code for protein and to the length of DNA contained in a chromomere is discussed.
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    Partial purification and properties of guanosine triphosphate cyclohydrolase from Drosophila melanogaster (1976)
    Springer
    Biochemical genetics 14 (1976), S. 259-270 
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    ISSN: 1573-4927
    Keywords: GTP cyclohydrolase ; Drosophila melanogaster ; pteridines ; dihydroneopterin triphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The first enzyme (named GTP cyclohydrolase) in the pathway for the biosynthesis of pteridines has been partially purified from extracts of late pupae and young adults of Drosophila melanogaster. This enzyme catalyzes the hydrolytic removal from GTP of carbon 8 as formate and the synthesis of 2-amino-4-hydroxy-6-(d-erythro-1′,2′,3′-trihydroxypropyl)-7,8-dihydropteridine triphosphate (dihydroneopterin triphosphate). Some of the properties of the enzyme are as follows: it functions optimally at pH 7.8 and at 42 C; activity is unaffected by KCl and NaCl, but divalent cations (Mg2+, Mn2+, Zn2+, and Ca2+) are inhibitory; the K m for GTP is 22 μm; and the molecular weight is estimated at 345,000 from gel filtration experiments. Of a number of nucleotides tested, only GDP and dGTP were used to any extent as substrate in place of GTP, and these respective compounds were used only 1.8% and 1.5% as well as GTP.
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    The suppressor of forked mutation in Drosophila melanogaster: Interactions with the lozenge gene (1976)
    Springer
    Biochemical genetics 14 (1976), S. 611-617 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; phenol oxidases ; spectrophotometry ; electrophoresis ; suppression ; ribosomal proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An interaction between the lozenge gene and the suppressor of forked gene of Drosophila melanogaster has been investigated both spectrophotometrically and electrophoretically. The nature of this interaction is such that certain lozenge alleles appear to be phenotypically suppressed while others are enhanced or unaffected, and the results reported demonstrate that the effect can clearly be observed at the biochemical level. Earlier observations have suggested that the suppressor of forked gene codes for a ribosomal protein, and this hypothesis is discussed.
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    Selection against homozygotes in the ADH polymorphic system of Drosophila melanogaster associated with the lethal factor l(2) Stm (1977)
    Springer
    Biochemical genetics 15 (1977), S. 93-100 
    Details
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase (ADH) ; genetic polymorphism ; selection ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In the natural populations +Tüb, +Prov, and +Rov, similar Adh F allele frequencies occur (q F=0.11, 0.18, and 0.08, respectively). However, there is a discrepancy in that the Adh F allele in +Tüb is closely linked to the lethal factor 1(2)Stm, which reduces relative fitness of the F phenotype to zero. In spite of this, polymorphism is maintained also in +Tüb, because the heterozygotes are superior to the homozygous S type (relative fitness=0.88). Under laboratory culture conditions, in +Tüb the relative fitness of the S genotype further decreases to 0.6. After outcrossing the lethal factor, relative fitnesses for S, FS, and F become 0.6, 1, and 0.48, respectively, implying that fitness for S remains the same. Relative values for S, FS, and F in +Prov, not affected by the lethal factor, are calculated by the maximum average fitness method to be 1, 1.2, and 0.2 under the assumption that heterozygous FS are similarly superior to S as in the natural +Tüb population and all allele frequencies found are stable equilibrium values.
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    Origin of α-glycerophosphate dehydrogenase isozymes in Drosophila melanogaster and their functional relationship in the α-glycerophosphate cycle (1977)
    Springer
    Biochemical genetics 15 (1977), S. 235-251 
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    ISSN: 1573-4927
    Keywords: l-glycerol-3-phosphate dehydrogenase (α-GPDH) ; isozymes ; development ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The basis for the differentiation of l-glycerol-3-phosphate dehydrogenase (α-GPDH) into larval and adult isozymes in Drosophila melanogaster was investigated by the correlation of a lack of appearance of each isozyme during development within Drosophila bearing α-GPDH “null” alleles and by the study of a putative conversion factor. Conversion studies indicate the presence of a heat-labile RNase-resistant conversion factor present in crude larval extracts with the ability to convert GPDH-1 to GPDH-2 and GPDH-3 but not vice versa. In addition, “null” mutations at the Gpdh locus obliterate all isozymatic species of α-GPDH in all developmental stages. These observations suggest that all α-GPDH isozymes are the product of a single structural gene and that the multiple forms of this enzyme arise during successive developmental stages through an epigenetic modification of the primary Gpdh + polypeptide. Finally, observations are reported which bear on the functional divergence of the α-glycerophosphate cycle in the adult and larval stage of development.
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    Isolation and genetic characterization of alcohol dehydrogenase thermostability variants occurring in natural populations of Drosophila melanogaster (1977)
    Springer
    Biochemical genetics 15 (1977), S. 971-988 
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    ISSN: 1573-4927
    Keywords: allozymes ; thermostability ; alcohol dehydrogenase ; Drosophila melanogaster ; natural populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Drosophila melanogaster collected from natural populations were examined fo thermostability variants within electrophoretic mobility classes of two enzymes. In alcohol dehydrogenase, two discrete forms of the “slow” allozyme and three discrete forms of the “fast” allozyme were revealed by postelectrophoretic treatments ranging from 15 sec at 40 C to 40 sec at 43 C. All variants have been mapped to within 0.7 unit of the Adh locus. Results of a geographic survey indicate that two alleles giving rise to fast-moderate and slow-moderate allozymes are common everywhere; other variants have a collective frequency ranging from 0% to 7%. In a test of the possibility that the rare Adh alleles could be generated by intragenic recombination between the two common alleles, electrophoresis and heat treatment of progeny recombinant for flanking markers of Adh revealed no new allozymes. Among 27 stocks containing slow α-glycerophosphate dehydrogenase allozymes and 109 fast stocks, heat treatments revealed no additional variation.
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    Control of drosopterin synthesis in Drosophila melanogaster: Mutants showing an altered pattern of GTP cyclohydrolase activity during development (1978)
    Springer
    Biochemical genetics 16 (1978), S. 13-26 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; GTP cyclohydrolase ; development ; pteridine biosynthesis ; mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The reaction catalyzed by GTP cyclohydrolase is the first unique step of pteridine biosynthesis in Drosophila melanogaster and is therefore likely to be an important control point. GTP cyclohydrolase activity varies during development, showing two distinct peaks of activity—one at pupariation and a much larger peak at emergence. Most of the early pupal enzyme is located in the body region, whereas in late pupal and early adult life most of the activity is found in the head. Mixing experiments indicate that developmental changes in activity are not due to changes in the level of a direct effector of GTP cyclohydrolase. The mutants raspberry and prune show an increased GTP cyclohydrolase activity at pupariation relative to wild type, but a decreased enzyme activity at emergence. The changes in GTP cyclohydrolase activity are reflected in changes in pteridine levels in these mutants. Several lines of evidence suggest that neither locus is the structural gene for GTP cyclohydrolase. The raspberry and prune gene products may play a specific role in regulating GTP cyclohydrolase activity during development.
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    A genetic and developmental analysis of an acid deoxyribonuclease in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 1113-1134 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; isozymes ; position effect ; segmental aneuploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A deoxyribonuclease, called DNase-1, that is active at acid pH in the presence of EDTA has been studied in Drosophila melanogaster. The locus for the enzyme maps genetically to 61.8 on the right arm of the third chromosome. Cytogenetically, DNase-1 has been localized to within five to ten bands between 90C-2 and 90E. This analysis utilizes both electrophoretic variants and the Y-autosome translocations of Lindsley et al. (1972). DNase-1 is present in all stages of the life cycle, and the paternal genome actively contributes DNase-1 to the embryo between 0 and 1 hr after fertilization.
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    Variation in amount of enzyme protein in natural populations (1978)
    Springer
    Biochemical genetics 16 (1978), S. 159-170 
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    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; allozyme properties and amounts ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Among strains of Drosophila melanogaster each derived from a single fertilized female taken from natural populations, there is variation in both alcohol dehydrogenase (ADH) activity and the amount of ADH protein. The correlation between ADH activity and number of molecules over all strains examined is 0.87 or 0.96 in late third instar larvae depending on whether the substrate is 2-propanol or ethanol. With respect to the two common electrophoretic allozymic forms, F and S, segregating in these populations, the FF strains on the whole have higher ADH activities and numbers of ADH molecules than the SS strains. Over all strains examined, enzyme extracts from FF strains have a mean catalytic efficiency per enzyme molecule higher than that of enzyme extracts from SS strains when ethanol is the substrate, and much higher when 2-propanol is the substrate. One FF strain had an ADH activity/ADH protein ratio characteristic of SS strains.
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    Alcohol metabolism in Drosophila melanogaster: Uselessness of the most active aldehyde oxidase produced by the Aldox locus (1978)
    Springer
    Biochemical genetics 16 (1978), S. 203-211 
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    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; alcohol tolerance ; alcohol utilization ; alcohol dehydrogenase ; aldehyde oxidase ; allozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Alcohol dehydrogenase is necessary for ethanol detoxification and metabolic utilization. It has been generally assumed that aldehyde oxidase (AO) produced by the Aldox locus (3–56.7) is necessary for a further transformation of acetaldehyde into acetate. We find that various mutant strains (ma-l or Aldox n) which do not produce an active enzyme show about the same tolerance to alcohol as do wild strains. This physiological paradox is probably to be explained by the discovery of another locus (not localized) which produced a small amount of AO in all tested strains. The adaptive significance of the genetically polymorphic Aldox locus is probably to be looked for in physiological pathways other than ethanol metabolism.
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    Electronic Resource
    A simple approach for discovering common nonelectrophoretic enzyme variability: A heat denaturation study in Drosophila melanogaster (1978)
    Springer
    Biochemical genetics 16 (1978), S. 299-305 
    Details
    ISSN: 1573-4927
    Keywords: nonelectrophoretic structural variability ; Drosophila melanogaster ; phosphoglucomutase ; genetic polymorphism ; heat denaturation study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A simple procedure is described to detect genetic heterogeneity within electrophoretic classes at a locus in Drosophila, based on electrophoresis and heat denaturation studies. Temperature-resistant (tr) and temperature-sensitive (ts) isoelectrophoretic alleles at the phosphoglucomutase locus (Pgm) are present at polymorphic frequencies in natural and in laboratory populations of Drosophila melanogaster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484086
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    Regulation of amylase activity in Drosophila melanogaster: Effects of dietary carbohydrate (1982)
    Springer
    Biochemical genetics 20 (1982), S. 1117-1129 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila melanogaster ; amylase ; dietary effects ; enzyme quantity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The level of amylase activity in larvae and adults of Drosophia melanogaster is dependent on the dietary carbohydrate source; flies or larvae from a food medium containing starch show higher levels of activity than individuals from a food containing simple sugars. This is shown to be due to repression of activity by sugars rather than enhancement of activity by starch. Moreover, the changes in enzyme activity reflect a change in enzyme quantity rather than a change in catalytic efficiency. The seeming stimulation of amylase activity by sucrose in some experiments is due, simply, to comparisons with “starvation” diets which cause a large nonspecific reduction in enzyme activity. Though all strains tested showed repression of enzyme activity by simple sugars, the degree of repression varies between strains. Also, in those strains which carry a duplication of the amylase structural gene, the two isozymal forms of amylase can be differentially repressed by dietary sugars.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00498936
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